Quinidine Gluconate

Class: Class Ia Antiarrhythmics
Note: This monograph also contains information on Quinidine Sulfate
VA Class: CV300
CAS Number: 7054-25-3

• Mortality


• 
  

  In many antiarrhythmic drug trials for non-life-threatening arrhythmias, active antiarrhythmic drug therapy was associated with increased mortality.^{163 167 168 169 170}

  
  


• 
  

  Risk associated with antiarrhythmic drug therapy probably is greatest in patients with structural heart disease.^{163 167 168 169 170}

  
  


• 
  

  A meta-analysis of data from several randomized, controlled studies in patients with atrial flutter and fibrillation indicates that quinidine therapy may be associated with a mortality rate >3 times higher than that associated with placebo.^{163 167 168 169 170}

  
  


• 
  

  A meta-analysis in patients with various non-life-threatening ventricular arrhythmias showed mortality associated with quinidine was consistently greater than that associated with various other antiarrhythmic agents (i.e., flecainide, mexiletine, propafenone, tocainide).^{163 167 168 169 170}

  
  

Introduction

Antiarrhythmic agent (class IA); antimalarial.^{119 161 163 167 168 169 170}

Uses for Quinidine Gluconate

Comparably effective to procainamide for atrial or ventricular arrhythmias; choice based on pharmacokinetics and adverse effect profile.^b

Supraventricular Tachyarrhythmias

Used principally for prophylactic therapy to maintain normal sinus rhythm after conversion of atrial fibrillation and/or flutter by other means.^b

Abnormal ventricular rate and CHF should first be controlled by administration of digoxin.^b Electrical cardioversion usually is considered the treatment of choice for conversion of atrial fibrillation or flutter.^b

Prevention of recurrence of atrial fibrillation or flutter is controversial because mortality may increase despite recurrence suppression.^b

May maintain normal sinus rhythm for long periods in recent onset of atrial fibrillation or flutter without CHF, atrial enlargement, or left ventricular hypertrophy, but long-standing atrial fibrillation is likely to recur even with quinidine maintenance therapy.^b

Generally, quinidine should not be used prophylactically for atrial fibrillation if the ventricular rate is adequately controlled by digoxin and the patient is asymptomatic.^b

Treatment of paroxysmal atrial tachycardia or paroxysmal AV junctional rhythm.^b

Atrial Premature Complexes

Treatment of atrial premature complexes; however, these arrhythmias usually are treated with digoxin.^b

Ventricular Premature Complexes (VPCs)

Treatment of VPCs; however, parenteral lidocaine is considered the drug of choice because quinidine can decrease myocardial contractility.^b

Like other antiarrhythmic drugs, not shown to decrease mortality rate in VPCs associated with AMI.^b

Avoid in treatment of asymptomatic VPCs.^b

Not for treatment of cardiac glycoside-induced ventricular arrhythmias.^b

VT

Treatment of paroxysmal VT that is not associated with complete heart block; however, treatment with cardioversion or lidocaine usually is preferred.^b

Suppression and prevention of recurrent ventricular arrhythmias (e.g., sustained VT) that in the judgment of the clinician are life-threatening.^b

Because of arrhythmogenic potential and the lack of evidence for improved survival for class I antiarrhythmic agents,^{146 147} not recommended for less severe VTs; avoid treatment in asymptomatic VPCs.^b

Malaria

Treatment of severe, life-threatening malaria caused by Plasmodium falciparum.^{101 102 104 105 119 122 124 126 142 153 158 162} Drug of choice for initial treatment of severe malaria.^{101 126 142 153 154 158 162}

Severe malaria usually is caused by P. falciparum and requires initial aggressive treatment with a parenteral antimalarial regimen initiated as soon as possible after diagnosis.^{158 162} Exchange transfusions can be considered if parasitemia is >10% or patient has cerebral malaria, altered mental status, non-volume-overload pulmonary edema, or renal complications.^{158 162}

For initial treatment of severe malaria in adults or children, CDC recommends a regimen of IV quinidine gluconate in conjunction with doxycycline, tetracycline, or clindamycin (oral or IV as tolerated).^{158 162} After at least 24 hours and when parasitemia is reduced to <1% and an oral regimen can be tolerated, IV quinidine gluconate can be discontinued and oral quinine sulfate initiated to complete 3 or 7 days of total quinidine and quinine therapy as determined by the geographic origin of the infecting parasite (3 days if malaria acquired in Africa or South America or 7 days if acquired in Southeast Asia).^{158 162}

Because of potentially fatal consequences of delays in initiating treatment of severe malaria, institutional pharmacy services should be aware of the essential role of ready availability of IV quinidine gluconate.^{142 143 153 158} (See Availability for Use in Treatment of Severe Malaria under Cautions.)

When IV quinidine gluconate is unavailable or cannot be used because of intolerance or contraindications, parasitemia is high or has not responded to quinidine gluconate therapy, and a parenteral regimen is indicated, IV artesunate is available from CDC under an investigational new drug (IND) protocol for the treatment of severe malaria.^{158 162 171 172} WHO and other clinicians recommend artesunate as a drug of choice for the treatment of severe malaria.^{101 173}

Although oral quinidine sulfate has been used for the treatment of malaria,^{167 170} including uncomplicated malaria† caused by multidrug-resistant P. falciparum,^{102 104 108 109 110 112} oral quinine sulfate is not included in CDC recommendations for treatment of uncomplicated or severe P. falciparum malaria.^{158 162}

Assistance with diagnosis or treatment of malaria and assistance obtaining IV quinidine gluconate or IV artesunate for treatment of severe malaria is available by contacting the CDC Malaria Hotline at 770-488-7788 from 8:00 a.m. to 4:30 p.m. Eastern Standard Time or CDC Emergency Operation Center at 770-488-7100 after hours, on weekends, and holidays.^{158 162 171 172}

Quinidine Gluconate Dosage and Administration

General

Arrhythmias

• 
  

  Initiate quinidine or adjust quinidine dosage in a setting where facilities and personnel for patient monitoring and resuscitation are continuously available, especially if used in patients with known structural heart disease or other risk factors for toxicity.^{163 167 168 169 170}

  
  


• 
  

  ECG monitoring of cardiac function and determination of plasma concentrations are recommended, especially when given IV or when >2 g is administered orally daily, and in patients with an increased risk of adverse reactions to quinidine (e.g., severe heart disease, hypotension, hepatic or renal disease).^b

  
  


• 
  

  Use for conversion of atrial fibrillation/flutter only after alternative measures (e.g., use of other drugs to control ventricular rate) have been inadequate.^{163 167 168 169 170} Discontinue quinidine if sinus rhythm is not restored within a reasonable amount of time.^{119 163 167 168 169 170}

  
  


• 
  

  Discontinue quinidine and consider other means of conversion if QRS complex widens to 130% of its pretreatment duration, QT_c interval widens to 130% of its pretreatment duration and is >500 milliseconds, P waves disappear, or patient develops clinically important tachycardia, symptomatic bradycardia, or hypotension.^{119 163 167 168 169 170}

  
  

Malaria

• 
  

  Initiate IV quinidine gluconate regimen as soon as possible after severe P. falciparum malaria is diagnosed.^{158 162} CDC recommends the regimen be initiated in patients with strong clinical evidence of severe malaria, even if initial blood smears do not demonstrate parasitemia or indicate P. vivax, P. ovale, or P. malariae infection.¹⁵⁸

  
  


• 
  

  CDC and others recommend the IV quinidine gluconate regimen be administered in an intensive care facility with close monitoring.^{101 111 122 123 124 125 126 141 153 158}

  
  


• 
  

  Monitor BP, plasma quinidine concentrations, and ECG closely and monitor blood glucose periodically in patients receiving quinidine for treatment of malaria; adjust dosage accordingly.^{101 102 104 111 141 158 162}

  
  


• 
  

  Because most deaths from severe malaria occur within the first 24–48 hours of illness, an initial loading dose is used to attain therapeutic plasma concentrations rapidly during this critical period of elevated parasitemia.¹⁵⁸ A loading dose should not be used if patient received >40 mg/kg of quinine in the previous 48 hours or received mefloquine in the previous 12 hours.¹⁵⁸

  
  


• 
  

  Calculate loading dose and infusion rate carefully to prevent acute cardiac events.¹⁵³ Consider that the risk of serious ventricular arrhythmias associated with quinidine is increased by bradycardia, hypokalemia, hypomagnesemia, and concomitant use of drugs that can prolong QT interval (e.g., halofantrine [an antimalarial drug not commercially available in the US], mefloquine, quinine).^{101 153 158}

  
  


• 
  

  CDC recommends consultation with a cardiologist and a clinician with experience in treating malaria.^{153 158 162} A cardiologist may be helpful if attempting to resume IV infusion of quinidine gluconate in patients who develop prolongation of QT interval or hypotension during treatment.¹⁵³

  
  

Administration

Administer quinidine sulfate orally.^{163 167} Administer quinidine gluconate orally^{168 169} or by IV infusion.¹¹⁹

IM administration of quinidine gluconate is not recommended because absorption may vary depending on the patient’s peripheral perfusion.¹¹⁹

Oral Administration

Administer quinidine sulfate orally as conventional^{167 170} or extended-release tablets.¹⁶³

Administer quinidine gluconate orally as extended-release tablets.^{168 169}

May be administered with food or antacids to decrease adverse GI effects.^b Avoid grapefruit juice.^{156 163 168 169} (See Specific Drugs and Foods under Interactions.)

To determine possible idiosyncrasy to quinidine, administer a test dose of 200 mg of quinidine sulfate orally several hours before initiating full dosage.^b For children, the test dose for idiosyncrasy is 2 mg/kg (up to 200 mg) of quinidine sulfate orally.^{164 b}

Extended-release Tablets

Used principally for maintenance therapy in the management of arrhythmias.^b

Quinidine gluconate extended-release tablets may be broken in half in order to titrate dosage; however, do not chew or crush.^{168 169}

IV Administration

Arrhythmias: Administer by IV infusion.¹¹⁹

Malaria: Administer by continuous or intermittent IV infusion.^{101 102 104 111 119 122 123 124 125 158 162}

Dilution

Arrhythmias: Dilute contents of multiple-dose vial containing 800 mg of quinidine gluconate (10 mL of 80-mg/mL injection) in 40 mL of 5% dextrose injection to provide solution containing 16 mg/mL.¹¹⁹

Malaria (continuous IV infusion regimen): Dilute loading dose of 6.25 mg/kg of quinidine (10 mg/kg of quinidine gluconate)^{101 119 141 153 158} in approximately 5 mL/kg of 0.9% sodium chloride injection.¹¹⁹

Malaria (intermittent IV infusion regimen): Dilute loading dose of 15 mg/kg of quinidine (24 mg/kg of quinidine gluconate)^{119 153 158} in 250 mL of 0.9% sodium chloride injection.¹¹⁹

Rate of Administration

Minimize length of IV tubing because of quinidine adsorption to PVC tubing.¹¹⁹ (See Compatibility under Stability.)

Overly rapid IV administration can cause potentially severe cardiovascular effects.¹¹⁹ (See IV Administration under Cautions.)

Arrhythmias: Up to 0.25 mg/kg per minute (i.e., about 1 mL/kg per hour of 16-mg/mL dilution).¹¹⁹

Malaria (continuous IV infusion regimen): Give loading dose of 6.25 mg/kg of quinidine (10 mg/kg of quinidine gluconate) by IV infusion over 1–2 hours, followed by continuous IV infusions given at a rate of 12.5 mcg/kg of quinidine per minute (20 mcg/kg of quinidine gluconate per minute) for at least 24 hours.^{101 119 153 158} Administer infusion at a rate that maintains a plasma quinidine concentration of 3–8 mcg/mL.¹⁵⁸ Decrease infusion rate or interrupt flow if corrected QT interval is >0.6 seconds, corrected QT interval exceeds baseline by >25%, QRS widening is >50% of baseline, or clinically important hypotension unresponsive to fluid expansion develops.^{111 124 128 158}

Malaria (intermittent IV infusion regimen): Give loading dose of 15 mg/kg of quinidine (24 mg/kg of quinidine gluconate) by IV infusion over 4 hours, followed 4 hours later (i.e., 8 hours after the beginning of the loading-dose infusion) by maintenance doses of 7.5 mg/kg of quinidine (12 mg/kg of quinidine gluconate) given by IV infusion over 4 hours at 8-hour intervals.^{119 153 158} Administer infusion at a rate that maintains a plasma quinidine concentration of 3–8 mcg/mL.¹⁵⁸ Decrease infusion rate or interrupt flow if corrected QT interval is >0.6 seconds, corrected QT interval exceeds baseline by >25%, QRS widening exceeds baseline by >50%, or clinically important hypotension unresponsive to fluid expansion develops.¹⁵⁸

Dosage

Available as quinidine sulfate^{163 167 170} and quinidine gluconate.^{119 168 169} Dosage for treatment of arrhythmias usually expressed in terms of the salt;^{119 163 167 168 169 170} dosage for treatment of malaria expressed in terms of the base or salt.^{119 158 162}

On a molar basis, approximately 267 mg of quinidine gluconate is equivalent to 200 mg of quinidine sulfate.^b

Each 100 mg of quinidine gluconate contains 62.5 mg of quinidine.¹¹⁹

Pediatric Patients

Quinidine Sulfate

Arrhythmias†

Oral

15–60 mg/kg of quinidine sulfate daily given in divided doses every 6 hours has been recommended by some clinicians.^{164 165} Others recommend 30 mg/kg daily or 900 mg/m² daily, given in 5 divided doses.^b

Quinidine Gluconate

Arrhythmias†

Oral

20–60 mg/kg of quinidine gluconate daily given in divided doses every 8 hours has been recommended by some clinicians.¹⁶⁵

IV

30 mg/kg daily or 900 mg/m² daily of quinidine gluconate, given in 5 divided doses, is recommended by some clinicians.^b

Severe Malaria

IV

Continuous IV infusion regimen: Initial loading dose of 6.25 mg/kg of quinidine (10 mg/kg of quinidine gluconate) given by IV infusion over 1–2 hours,^{101 119 158 162} followed by a maintenance infusion of 12.5 mcg/kg of quinidine per minute (20 mcg/kg of quinidine gluconate per minute) continued for ≥24 hours and until parasitemia is reduced to <1% and oral quinine sulfate can be substituted.^{101 111 119 122 123 124 125 141 158 162} Some clinicians state initial loading dose should not exceed 375 mg of quinidine (600 mg of quinidine gluconate).¹⁰¹

Intermittent IV infusion regimen: Initial loading dose of 15 mg/kg of quinidine (24 mg/kg of quinidine gluconate) given by IV infusion over 4 hours, followed 4 hours later (i.e., 8 hours after the beginning of the loading-dose infusion) by maintenance doses of 7.5 mg/kg of quinidine (12 mg/kg of quinidine gluconate) given by IV infusion over 4 hours at 8-hour intervals until 3 maintenance doses have been administered and parasitemia is reduced to <1% and oral quinine sulfate can be substituted.^{119 153 158 162}

After ≥24 hours of quinidine gluconate and when clinically indicated, switch to oral quinine sulfate therapy to complete a total of 3 or 7 days of total quinidine and quinine therapy as determined by the geographic origin of the infecting parasite (3 days if malaria was acquired in Africa or South America or 7 days if acquired in Southeast Asia).^{122 123 141 158 162}

The IV quinidine gluconate regimen followed by oral quinine sulfate is used in conjunction with a 7-day regimen of doxycycline, tetracycline, or clindamycin (given IV or orally as tolerated).¹⁵⁸

Adults

Quinidine Sulfate

Arrhythmias

Oral

Conversion of atrial fibrillation/flutter (conventional tablets): Manufacturers recommend 400 mg of quinidine sulfate (332 mg of quinidine) every 6 hours initially; dose may be cautiously increased if conversion is not attained after 4 or 5 doses.^{167 170}

Conversion of atrial fibrillation/flutter (extended-release tablets): Manufacturer recommends 300 mg of quinidine sulfate (249 mg of quinidine) every 8–12 hours initially; dose may be cautiously increased if conversion not attained, quinidine serum concentrations are within the therapeutic range, and the drug is well tolerated.¹⁶³

If successful conversion of atrial fibrillation does not occur when quinidine serum concentrations are in the therapeutic range, further dosage increases generally are unsuccessful and increase the possibility of toxicity.^b

Reduction in frequency of relapse into atrial fibrillation/flutter (conventional tablets): Manufacturers recommend 200 mg of quinidine sulfate (166 mg of quinidine) every 6 hours initially.^{167 170} Dose may be cautiously increased if well tolerated, serum quinidine concentrations are within therapeutic range, and average time between arrhythmic episodes has not been satisfactorily increased.^{167 170} Use such prophylaxis only if alternative measures have been inadequate and if potential benefits outweigh risks;^{167 170} consider mortality risk.^{167 170}

Reduction in frequency of relapse into atrial fibrillation/flutter (extended-release tablets): Manufacturer recommends 300 mg of quinidine sulfate (249 mg of quinidine) every 8–12 hours initially.¹⁶³ Dose may be cautiously increased if well tolerated, serum quinidine concentrations are within therapeutic range, and average time between arrhythmic episodes has not been satisfactorily increased.¹⁶³ Use such prophylaxis only if alternative measures have been inadequate and if potential benefits outweigh risks;¹⁶³ consider mortality risk.¹⁶³

Manufacturers state that dosage regimens for suppression of life-threatening ventricular arrhythmias have not been adequately studied, but regimens similar to those used in the management of atrial fibrillation/flutter have been described.^{163 167 170} Whenever possible, such therapy should be guided by results of programmed electrical stimulation and/or Holter monitoring with exercise.^{163 167 170}

Malaria

Oral

300–600 mg or 10 mg/kg of quinidine sulfate every 8 hours for 5–7 days has been used for the treatment of uncomplicated P. falciparum malaria.^{102 103 108 109 110}

Not included in CDC recommendations for treatment of uncomplicated or severe malaria.^{158 162} (See Malaria under Uses.)

Quinidine Gluconate

Arrhythmias

Oral

Conversion of atrial fibrillation/flutter (extended-release tablets): Manufacturers recommend 648 mg of quinidine gluconate (403 mg of quinidine) every 8 hours initially; dose may be cautiously increased if conversion is not attained after 3 or 4 doses.^{168 169} Alternatively, manufacturers state that a regimen of 324 mg of quinidine gluconate (202 mg of quinidine) may be given every 8 hours for 2 days, then 648 mg of quinidine gluconate (403 mg of quinidine) every 12 hours for 2 days, and then 648 mg of quinidine gluconate (403 mg of quinidine) every 8 hours for up to 4 days.^{168 169} If the 648-mg dose is not tolerated, the lower dosage can be continued for the last 4 days.^{168 169}

Reduction in frequency of relapse into atrial fibrillation/flutter (extended-release tablets): Manufacturers recommend 324 mg of quinidine gluconate (202 mg of quinidine) every 8 or 12 hours initially.^{168 169} Dose may be cautiously increased if well tolerated, serum quinidine concentrations are within therapeutic range, and average time between arrhythmic episodes has not been satisfactorily increased.^{168 169} Use such prophylaxis only if alternative measures have been inadequate and if potential benefits outweigh risks;^{168 169} consider mortality risk.^{168 169}

Manufacturers state that dosage regimens for suppression of life-threatening ventricular arrhythmias have not been adequately studied, but regimens similar to those used in the management of atrial fibrillation/flutter have been described.^{168 169} Whenever possible, such therapy should be guided by results of programmed electrical stimulation and/or Holter monitoring with exercise.^{168 169}

IV

Treatment of symptomatic atrial fibrillation/flutter: Initially, up to 0.25 mg/kg of quinidine gluconate per minute (i.e., up to 1 mL/kg per hour) of 16-mg/mL dilution.¹¹⁹ Discontinue IV infusion as soon as sinus rhythm is restored.¹¹⁹

Most arrhythmias responsive to IV quinidine respond to a total IV dosage <5 mg/kg, although 10 mg/kg may be required in some patients.¹¹⁹ If conversion to sinus rhythm has not occurred after infusion of quinidine gluconate 10 mg/kg, discontinue the infusion and consider other means of cardioversion.¹¹⁹

Although dosing regimens for the management of life-threatening ventricular arrhythmias have not been systematically evaluated, regimens similar to that used in the management of atrial fibrillation/flutter have been described.¹¹⁹

Severe Malaria

IV

Continuous IV infusion regimen: Initial loading dose of 6.25 mg/kg of quinidine (10 mg/kg of quinidine gluconate) given by IV infusion over 1–2 hours,^{101 119 141 158 162} followed by a maintenance infusion of 12.5 mcg/kg of quinidine per minute (20 mcg/kg of quinidine gluconate per minute) continued for ≥24 hours and until parasitemia is reduced to <1% and oral quinine sulfate can be substituted.^{101 111 119 122 123 124 125 141 158 162} Some clinicians state initial loading dose should not exceed 375 mg of quinidine (600 mg of quinidine gluconate).¹⁰¹

Intermittent IV infusion regimen: Initial loading dose of 15 mg/kg of quinidine (24 mg/kg of quinidine gluconate) given by IV infusion over 4 hours, followed 4 hours later (i.e., 8 hours after the beginning of the loading-dose infusion) by maintenance doses of 7.5 mg/kg of quinidine (12 mg/kg of quinidine gluconate) given by IV infusion over 4 hours at 8-hour intervals until 3 maintenance doses have been administered and parasitemia is reduced to <1% and oral quinine sulfate can be substituted.^{119 153 158 162}

After ≥24 hours of quinidine gluconate and when clinically indicated, switch to oral quinine sulfate therapy to complete a total of 3 or 7 days of total quinidine and quinine therapy as determined by the geographic origin of the infecting parasite (3 days if malaria was acquired in Africa or South America or 7 days if acquired in Southeast Asia).^{122 123 141 158}

The IV quinidine gluconate regimen followed by oral quinine sulfate is used in conjunction with a 7-day regimen of doxycycline, tetracycline, or clindamycin (given IV or orally as tolerated).^{158 162}

Prescribing Limits

Pediatric Patients

Arrhythmias†

Quinidine Gluconate or Quinidine Sulfate

Oral

2.4 g of quinidine sulfate or quinidine gluconate daily.¹⁶⁵

Severe Malaria

Quinidine Gluconate

IV

Continuous IV infusion regimen: Maximum initial loading dose of 375 mg of quinidine (600 mg of quinidine gluconate).¹⁰¹

Adults

Severe Malaria

Quinidine Gluconate

IV

Continuous IV infusion regimen: Maximum initial loading dose of 375 mg of quinidine (600 mg of quinidine gluconate).¹⁰¹

Special Populations

Hepatic Impairment

Dosage reduction may be necessary to avoid toxicity.^{119 163 167 168 169 170}

Renal Impairment

Dosage reduction may be necessary to avoid toxicity.^{119 163 167 168 169 170}

In patients with severe malaria receiving IV quinidine gluconate, CDC states that initial (including loading) doses do not need to be reduced in those with renal failure.¹⁵⁸ If renal failure persists or clinical improvement does not occur in such patients, CDC recommends reducing maintenance IV infusion rate by one-third to one-half on the third day of treatment.¹⁵⁸

CHF

Dosage reduction may be necessary to avoid toxicity.^{119 163 167 168 169 170}

Geriatric Patients

Select dosage with caution, usually starting at the low end of the dosage range, and consider age-related decreases in hepatic, renal, and/or cardiac function and concomitant disease and drug therapy.¹¹⁹

Cautions for Quinidine Gluconate

Contraindications

• 
  

  Patients with AV junctional or idioventricular pacemaker, including those in complete AV block.^{119 163 167 168 169 170}

  
  


• 
  

  History of quinidine- or quinine-associated thrombocytopenic purpura.^{119 163 167 168 169 170}

  
  


• 
  

  Myasthenia gravis or other conditions that might be adversely affected by anticholinergic effects.^{119 163 167 168 169 170}

  
  


• 
  

  Known hypersensitivity to quinidine.^{119 163 167 168 169 170}

  
  

Warnings/Precautions

Warnings

Mortality

Pooled analysis of data from several randomized, controlled studies in patients with ventricular arrhythmias indicates that mortality rate associated with quinidine therapy is at least as high as that associated with other antiarrhythmic agents (e.g., flecainide, mexiletine, propafenone, tocainide).^b

Use quinidine only for life-threatening arrhythmias.¹⁴⁵ Avoid use for less severe ventricular arrhythmias and treatment of asymptomatic VPCs.¹⁴⁵

Additionally, pooled analysis of data from several randomized, controlled studies in patients with atrial flutter and fibrillation indicates that quinidine therapy may be associated with a mortality rate more than 3 times higher than that associated with placebo;^{163 167 168 169 170} consider the increased risk of death when initiating quinidine therapy.¹⁴⁴

Use with extreme caution, if at all, in patients with incomplete AV nodal block, since complete heart block and asystole may result.^b Parenteral administration is especially hazardous in the presence of AV block, in the absence of atrial activity, and in patients with extensive myocardial injury.^b

Proarrhythmic Effects

The possibility that potentially serious cardiac arrhythmias, including torsades de pointes, could occur if used concomitantly with other drugs that prolong the QT_c interval should be considered and such combined use should be avoided.¹⁵¹

Hypokalemia, hypoxia, and disorders of acid-base balance must be eliminated as potentiating factors in patients who require large doses of antiarrhythmic agents to control ventricular arrhythmias.^b

Paradoxical Increase in Ventricular Rate in Atrial Flutter/Fibrillation

Paradoxically, an extremely rapid ventricular rate may occur when used in the treatment of atrial flutter or fibrillation, due to a reduction in the degree of AV nodal block to a 1:1 ratio.^b The anticholinergic action on the AV node also may increase the heart rate.^b

This tachycardia may be prevented by prior digitalization.^b

If cessation of atrial fibrillation or flutter is accompanied by depression of the normal pacemaker, an idioventricular rhythm (including ventricular tachycardia and fibrillation) may result.^b

Exacerbated Bradycardia in Sick Sinus Syndrome

Possible marked sinus node depression and bradycardia.^b

IV Administration

Overly rapid IV administration may cause peripheral vascular collapse and hypotension.¹¹⁹

Sensitivity Reactions

Hypersensitivity Reactions

Idiosyncratic and hypersensitivity reactions to quinidine may occur, and the reaction to a test dose or the first dose of the drug should be observed carefully.^b (See Oral Administration under Dosage and Administration.)

Observe for hypersensitivity for the first weeks of therapy.^b

Symptoms of cinchonism such as tinnitus, headache, vertigo, fever, dizziness, lightheadedness, tremor, nausea, and disturbed vision may occur in sensitive patients after a single dose.^b

Decrease dosage if signs of cinchonism appear.^b

General Precautions

Cardiovascular Effects

Possible syncope, probably due to ventricular tachycardia or fibrillation in usual doses.^b May subside spontaneously, but occasionally are fatal.^b If quinidine-induced syncope occurs, discontinue the drug.^b Also may cause bradycardia.^b

Severe hypotension may occur following IV administration or oral overdosage.^b Vascular collapse, respiratory distress, and respiratory arrest may occur.^b Reportedly related to the dose and rate of administration of the drug.^{102 107 119} Rapid IV injection of as little as 200 mg reportedly may cause a decrease in blood pressure of 40–50 mm Hg.¹¹⁹ Norepinephrine or metaraminol may be used if necessary to treat vascular collapse; artificial respiration and other supportive measures may be required.^b

While substantial cardiovascular toxicity generally has not occurred, ECG changes, including prolonged QT interval, widened QRS complex, and flattened T waves (without dysrhythmia), have occurred frequently and hypotension and ventricular tachycardia have occurred occasionally in patients receiving IV quinidine gluconate for the treatment of Plasmodium falciparum malaria.^{102 104 108 124}

Use with caution in patients without implanted pacemakers at high risk of complete atrioventricular block (e.g., digitalis intoxication, second-degree atrioventricular block, severe intraventricular conduction defects).^{163 167 168 169 170}

Availability for Use in Treatment of Severe Malaria

Because of potentially fatal consequences of delays in initiating treatment of severe malaria, institutional pharmacy services should be aware of the essential role of ready availability of IV quinidine gluconate.^{b 142 143 153 158}

If IV quinidine gluconate is not readily available for a patient with severe P. falciparum malaria (e.g., in hospitals where the drug is not maintained on formulary or otherwise available), health-care professionals should contact a nearby healthcare facility that stocks the drug.¹⁵⁸ If a local source cannot be found, contact the local or regional distributor of the drug.¹⁵⁸

If IV quinidine gluconate is unavailable, cannot be used because of intolerance or contraindications, or parasitemia is high or has not responded to quinidine gluconate therapy, IV artesunate is available from the CDC under an IND protocol for treatment of severe malaria.^{158 162 171} (See Malaria under Uses.)

Specific Populations

Pregnancy

Category C.^{119 163 166 167 168 169 170}

Generally considered relatively safe at usual dosages, but may exhibit oxytocic effect (possible abortion) at high dosages.¹⁶⁶

Lactation

Distributed into milk.^{119 163 166 167 168 169 170} Avoid, if possible, in nursing women.^{119 163 167 168 169 170}

Pediatric Use

Safety and efficacy as an antiarrhythmic agent in children not established.^{119 163 167 168 169 170} Has been used in children with arrhythmias†.^{165 b}

Study and experience in children with malaria suggest that safety and efficacy of IV quinidine gluconate are similar to those in adults.¹¹⁹

Geriatric Use

Safety and efficacy not systematically studied in geriatric patients.^{119 167 168 169 170} Clinical studies did not include sufficient numbers of patients ≥65 years of age to determine whether they respond differently than younger adults;¹¹⁹ other reported clinical experience has not identified differences in responses between geriatric adults and younger patients.¹¹⁹

When used in geriatric patients, select dosage with caution, usually initiating therapy at the low end of dosage range, and consider the greater frequency of decreased hepatic, renal, and/or cardiac function and concomitant disease and drug therapy in this age group.¹¹⁹

Hepatic Impairment

Decreased clearance;^{119 163 167 168}

Q-Bid LA

Generic Name: guaifenesin (gwye FEN e sin)

Brand Names: Duratuss G, Ganidin NR, GG 200 NR, GuaiFENesin LA, Liquibid, Muco-Fen 1200, Organidin NR, Q-Bid LA, Robitussin, Scot-Tussin

What is Q-Bid LA (guaifenesin)?

Guaifenesin is an expectorant. It helps loosen congestion in your chest and throat, making it easier to cough out through your mouth.

Guaifenesin is used to reduce chest congestion caused by the common cold, infections, or allergies.

Guaifenesin may also be used for purposes not listed in this medication guide.

What is the most important information I should know about Q-Bid LA (guaifenesin)?

You should not use this medicine if you are allergic to guaifenesin.

Use this medication exactly as directed on the label, or as prescribed by your doctor. Do not use it in larger amounts or for longer than recommended.

Do not give this medication to a child younger than 4 years old. Always ask a doctor before giving a cough or cold medicine to a child. Death can occur from the misuse of cough and cold medicines in very young children. Drink extra fluids to help loosen the congestion and lubricate your throat while you are taking this medication. This medication may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.

What should I discuss with my healthcare provider before taking Q-Bid LA (guaifenesin)?

You should not use this medicine if you are allergic to guaifenesin. FDA pregnancy category C. It is not known whether guaifenesin will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medication. It is not known whether guaifenesin passes into breast milk or if it could harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

How should I take Q-Bid LA (guaifenesin)?

Use exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.

Do not give this medication to a child younger than 4 years old. Always ask a doctor before giving a cough or cold medicine to a child. Death can occur from the misuse of cough and cold medicines in very young children. Drink extra fluids to help loosen the congestion and lubricate your throat while you are taking this medication. Take guaifenesin with food if it upsets your stomach.

Measure the liquid form of guaifenesin with a special dose-measuring spoon or cup, not a regular table spoon. If you do not have a dose-measuring device, ask your pharmacist for one.

Do not crush, chew, break, or open a controlled-release, delayed-release, or extended-release tablet or capsule. Swallow it whole. Breaking or opening the pill may cause too much of the drug to be released at one time. Store at room temperature away from moisture, heat, and direct sunlight.

What happens if I miss a dose?

Since cough medicine is taken when needed, you may not be on a dosing schedule. If you are taking the medication regularly, take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking Q-Bid LA (guaifenesin)?

This medication may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.

Q-Bid LA (guaifenesin) side effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Less serious side effects may include:

• 
  

  dizziness or headache,

  
  


• 
  

  a rash, or

  
  


• 
  

  nausea, vomiting, or stomach upset.

  
  

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect guaifenesin ?

There may be other drugs that can interact with guaifenesin. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor.

More Q-Bid LA resources

• Q-Bid LA Side Effects (in more detail)
• Q-Bid LA Use in Pregnancy & Breastfeeding
• Q-Bid LA Support Group
• 0 Reviews for Q-Bid LA - Add your own review/rating

• Allfen MedFacts Consumer Leaflet (Wolters Kluwer)


• Allfen Advanced Consumer (Micromedex) - Includes Dosage Information


• Guaifenesin Monograph (AHFS DI)


• Guaifenesin Granules MedFacts Consumer Leaflet (Wolters Kluwer)


• Guaifenesin NR Prescribing Information (FDA)


• Hytuss Immediate-Release Capsules MedFacts Consumer Leaflet (Wolters Kluwer)


• Mucinex Prescribing Information (FDA)


• Mucinex Sustained-Release Tablets MedFacts Consumer Leaflet (Wolters Kluwer)


• Mucinex Consumer Overview


• Organidin NR Prescribing Information (FDA)


• Tussin Consumer Overview

Compare Q-Bid LA with other medications

• Bronchitis
• Cough
• Fibromyalgia

Where can I get more information?

• Your pharmacist can provide more information about guaifenesin.

See also: Q-Bid LA side effects (in more detail)

Quenalin

Generic Name: diphenhydramine (DYE fen HYE dra meen)

Brand Names: Aler-Tab, Allergy, Allermax, Altaryl, Benadryl Allergy, Benadryl DF, Benadryl Dye Free Allergy, Benadryl Ultratab, Children's Allergy, Diphen Cough, Diphenhist, Dytuss, PediaCare Children's Allergy, Q-Dryl, Q-Dryl A/F, Siladryl, Siladryl Allergy, Silphen Cough, Simply Sleep, Sleep-ettes, Sleep-ettes D, Sominex Maximum Strength Caplet, Theraflu Thin Strips Multi Symptom, Triaminic Thin Strips Cough & Runny Nose, Unisom Sleepgels Maximum Strength, Valu-Dryl

What is Quenalin (diphenhydramine)?

Diphenhydramine is an antihistamine. Diphenhydramine blocks the effects of the naturally occurring chemical histamine in the body.

Diphenhydramine is used to treat sneezing; runny nose; itching, watery eyes; hives; rashes; itching; and other symptoms of allergies and the common cold.

Diphenhydramine is also used to suppress coughs, to treat motion sickness, to induce sleep, and to treat mild forms of Parkinson's disease.

Diphenhydramine may also be used for purposes other than those listed in this medication guide.

What is the most important information I should know about Quenalin (diphenhydramine)?

Use caution when driving, operating machinery, or performing other hazardous activities. Diphenhydramine may cause dizziness or drowsiness. If you experience dizziness or drowsiness, avoid these activities. Use alcohol cautiously. Alcohol may increase drowsiness and dizziness while taking diphenhydramine.

What should I discuss with my healthcare provider before taking Quenalin (diphenhydramine)?

Do not take diphenhydramine if you have taken a monoamine oxidase inhibitor (MAOI) such as isocarboxazid (Marplan), phenelzine (Nardil), or tranylcypromine (Parnate) in the last 14 days. A very dangerous drug interaction could occur, leading to serious side effects.

Before taking this medication, tell your doctor if you have

• 
  

  glaucoma or increased pressure in the eye;

  
  


• 
  

  a stomach ulcer;

  
  


• 
  

  an enlarged prostate, bladder problems or difficulty urinating;

  
  


• 
  

  an overactive thyroid (hyperthyroidism);

  
  


• 
  

  hypertension or any type of heart problems; or

  
  


• 
  

  asthma.

  
  

You may not be able to take diphenhydramine, or you may require a lower dose or special monitoring during treatment if you have any of the conditions listed above.

Diphenhydramine is in the FDA pregnancy category B. This means that it is not expected to be harmful to an unborn baby. Do not take diphenhydramine without first talking to your doctor if you are pregnant. Infants are especially sensitive to the effects of antihistamines, and side effects could occur in a breast-feeding baby. Do not take diphenhydramine without first talking to your doctor if you are nursing a baby. If you are over 60 years of age, you may be more likely to experience side effects from diphenhydramine. You may require a lower dose of this medication.

How should I take Quenalin (diphenhydramine)?

Take diphenhydramine exactly as directed on the package or as directed by your doctor. If you do not understand these directions, ask your pharmacist, nurse, or doctor to explain them to you.

Take each dose with a full glass of water.

Diphenhydramine can be taken with or without food.

For motion sickness, a dose is usually taken 30 minutes before motion, then with meals and at bedtime for the duration of exposure.

As a sleep aid, diphenhydramine should be taken approximately 30 minutes before bedtime.

To ensure that you get a correct dose, measure the liquid forms of diphenhydramine with a special dose-measuring spoon or cup, not with a regular tablespoon. If you do not have a dose-measuring device, ask your pharmacist where you can get one.

Never take more of this medication than is prescribed for you. The maximum amount of diphenhydramine that you should take in any 24-hour period is 300 mg.

Store diphenhydramine at room temperature away from moisture and heat.

What happens if I miss a dose?

Take the missed dose as soon as you remember. However, if it is almost time for the next dose, skip the missed dose and take only the next regularly scheduled dose. Do not take a double dose of this medication unless otherwise directed by your doctor.

What happens if I overdose?

Seek emergency medical attention if an overdose is suspected.

Symptoms of a diphenhydramine overdose include extreme sleepiness, confusion, weakness, ringing in the ears, blurred vision, large pupils, dry mouth, flushing, fever, shaking, insomnia, hallucinations, and possibly seizures.

What should I avoid while taking Quenalin (diphenhydramine)?

Use caution when driving, operating machinery, or performing other hazardous activities. Diphenhydramine may cause dizziness or drowsiness. If you experience dizziness or drowsiness, avoid these activities. Use alcohol cautiously. Alcohol may increase drowsiness and dizziness while taking diphenhydramine.

Quenalin (diphenhydramine) side effects

Stop taking diphenhydramine and seek emergency medical attention if you experience an allergic reaction (difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives).

Other, less serious side effects may be more likely to occur. Continue to take diphenhydramine and talk to your doctor if you experience

• 
  

  sleepiness, fatigue, or dizziness;

  
  


• 
  

  headache;

  
  


• 
  

  dry mouth; or

  
  


• 
  

  difficulty urinating or an enlarged prostate.

  
  

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect Quenalin (diphenhydramine)?

Do not take diphenhydramine if you have taken a monoamine oxidase inhibitor (MAOI) such as isocarboxazid (Marplan), phenelzine (Nardil), or tranylcypromine (Parnate) in the last 14 days. A very dangerous drug interaction could occur, leading to serious side effects.

Talk to your pharmacist before taking other over-the-counter cough, cold, allergy, or insomnia medications. These products may contain medicines similar to diphenhydramine, which could lead to an antihistamine overdose.

Before taking this medication, tell your doctor if you are taking any of the following medicines:

• 
  

  anxiety or sleep medicines such as alprazolam (Xanax), diazepam (Valium), chlordiazepoxide (Librium), temazepam (Restoril), or triazolam (Halcion);

  
  


• 
  

  medications for depression such as amitriptyline (Elavil), doxepin (Sinequan), nortriptyline (Pamelor), fluoxetine (Prozac), sertraline (Zoloft), or paroxetine (Paxil); or

  
  


• 
  

  any other medications that make you feel drowsy, sleepy, or relaxed.

  
  

Drugs other than those listed here may also interact with diphenhydramine. Talk to your doctor and pharmacist before taking any prescription or over-the-counter medicines, including vitamins, minerals, and herbal products.

More Quenalin resources

• Quenalin Side Effects (in more detail)
• Quenalin Use in Pregnancy & Breastfeeding
• Quenalin Drug Interactions
• Quenalin Support Group
• 0 Reviews for Quenalin - Add your own review/rating

• Banophen MedFacts Consumer Leaflet (Wolters Kluwer)


• Ben-Tann Suspension MedFacts Consumer Leaflet (Wolters Kluwer)


• Benadryl Consumer Overview


• Benadryl Cream MedFacts Consumer Leaflet (Wolters Kluwer)


• Benadryl Allergy Chewable Tablets MedFacts Consumer Leaflet (Wolters Kluwer)


• Children's Allergy Prescribing Information (FDA)


• Diphen Advanced Consumer (Micromedex) - Includes Dosage Information


• Diphenhydramine MedFacts Consumer Leaflet (Wolters Kluwer)


• Diphenhydramine Prescribing Information (FDA)


• Diphenhydramine Hydrochloride Monograph (AHFS DI)


• Diphenoxylate Hydrochloride Monograph (AHFS DI)


• Dytuss Elixir MedFacts Consumer Leaflet (Wolters Kluwer)


• Simply Sleep MedFacts Consumer Leaflet (Wolters Kluwer)


• Sominex MedFacts Consumer Leaflet (Wolters Kluwer)

Compare Quenalin with other medications

• Allergic Reactions
• Cold Symptoms
• Cough
• Extrapyramidal Reaction
• Hay Fever
• Insomnia
• Motion Sickness
• Nausea/Vomiting
• Pruritus
• Urticaria

Where can I get more information?

• Your pharmacist can provide more information about diphenhydramine.

See also: Quenalin side effects (in more detail)

Quadratuss

Pronunciation: car-beta-PEN-tane/klor-fen-EER-a-meen/e-FED-rin/fen-ill-EF-rin
Generic Name: Carbetapentane/Chlorpheniramine/Ephedrine/Phenylephrine
Brand Name: Examples include Quadratuss and Rynatuss

Quadratuss is used for:

Relieving symptoms of sinus congestion, runny nose, sneezing, and cough due to colds, upper respiratory infections, and allergies. It may also be used for other conditions as determined by your doctor.

Quadratuss is a decongestant, antihistamine, and cough suppressant combination. It works by constricting blood vessels and reducing swelling in the nasal passages. The antihistamine works by blocking the action of histamine, which helps reduce symptoms, such as watery eyes and sneezing, while the cough suppressant works in the brain to help decrease the cough reflex to reduce a dry cough.

Do NOT use Quadratuss if:

• you are allergic to any ingredient in Quadratuss


• you have severe high blood pressure, severe heart blood vessel disease, rapid heartbeat, or severe heart problems


• you are unable to urinate or are having an asthma attack


• you take sodium oxybate (GHB) or you have taken furazolidone or a monoamine oxidase (MAO) inhibitor (eg, phenelzine) within the last 14 days

Contact your doctor or health care provider right away if any of these apply to you.

Before using Quadratuss:

Some medical conditions may interact with Quadratuss. Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

• if you are pregnant, planning to become pregnant, or are breast-feeding


• if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement


• if you have allergies to medicines, foods, or other substances


• if you have a fast, slow, or irregular heartbeat


• if you have a history of adrenal gland problems (eg, adrenal gland tumor); heart problems; high blood pressure; diabetes; heart blood vessel problems; stroke; glaucoma; a blockage of your bladder, stomach, or intestines; ulcers; trouble urinating; an enlarged prostate or other prostate problems; seizures; or an overactive thyroid


• if you have a history of asthma, chronic cough, lung problems (eg, chronic bronchitis, emphysema), or chronic obstructive pulmonary disease (COPD), or if your cough occurs with large amounts of mucus

Some MEDICINES MAY INTERACT with Quadratuss. Tell your health care provider if you are taking any other medicines, especially any of the following:

• Beta-blockers (eg, propranolol), catechol-O-methyltransferase (COMT) inhibitors (eg, tolcapone), furazolidone, indomethacin, MAO inhibitors (eg, phenelzine), sodium oxybate (GHB), or tricyclic antidepressants (eg, amitriptyline) because side effects of Quadratuss may be increased


• Digoxin or droxidopa because risk of irregular heartbeat or heart attack may be increased


• Bromocriptine or hydantoins (eg, phenytoin) because side effects ma y be increased by Quadratuss


• Guanadrel, guanethidine, mecamylamine, methyldopa, or reserpine because effectiveness may be decreased by Quadratuss

This may not be a complete list of all interactions that may occur. Ask your health care provider if Quadratuss may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

How to use Quadratuss:

Use Quadratuss as directed by your doctor. Check the label on the medicine for exact dosing instructions.

• Quadratuss may be taken with or without food.


• If you miss a dose of Quadratuss, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once.

Ask your health care provider any questions you may have about how to use Quadratuss.

Important safety information:

• Quadratuss may cause dizziness, drowsiness, or blurred vision. Do not drive, operate machinery, or do anything else that could be dangerous until you know how you react to Quadratuss. Using Quadratuss alone, with certain other medicines, or with alcohol may lessen your ability to drive or perform other potentially dangerous tasks.


• Do not take diet or appetite control medicines while you are taking Quadratuss without checking with your doctor.


• Quadratuss contains phenylephrine. Before you begin taking any new prescription or nonprescription medicine, read the ingredients to see if it also contains phenylephrine. If it does or if you are uncertain, contact your doctor or pharmacist.


• Do NOT exceed the recommended dose or take Quadratuss for longer than prescribed without checking with your doctor.


• If your symptoms do not improve within 5 to 7 days or if they become worse, check with your doctor.


• Quadratuss may cause increased sensitivity to the sun. Avoid exposure to the sun, sunlamps, or tanning booths until you know how you react to Quadratuss. Use a sunscreen or protective clothing if you must be outside for a prolonged period.


• If you are scheduled for allergy skin testing, do not take Quadratuss for several days before the test because it may decrease your response to the skin tests.


• Before you have any medical or dental treatments, emergency care, or surgery, tell the doctor or dentist that you are using Quadratuss.


• Use Quadratuss with caution in the ELDERLY because they may be more sensitive to its effects.


• Caution is advised when using Quadratuss in CHILDREN because they may be more sensitive to its effects.


• PREGNANCY and BREAST-FEEDING: If you become pregnant while taking Quadratuss, discuss with your doctor the benefits and risks of using Quadratuss during pregnancy. It is unknown if Quadratuss is excreted in breast milk. Do not breast-feed while taking Quadratuss.

Possible side effects of Quadratuss:

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome:

Constipation; diarrhea; dizziness; drowsiness; excitability; headache; loss of appetite; nausea; nervousness or anxiety; trouble sleeping; upset stomach; vomiting; weakness.

Seek medical attention right away if any of these SEVERE side effects occur:

Severe allergic reactions (rash; hives; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); difficulty urinating or inability to urinate; fast or irregular heartbeat; hallucinations; seizures; severe dizziness, lightheadedness, or headache; tremor; trouble sleeping; vision changes.

This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider. Call your doctor for medical advice about side effects. To report side effects to the appropriate agency, please read the Guide to Reporting Problems to FDA.

See also: Quadratuss side effects (in more detail)

If OVERDOSE is suspected:

Contact 1-800-222-1222 (the American Association of Poison Control Centers), your local poison control center, or emergency room immediately. Symptoms may include blurred vision; confusion; hallucinations; seizures; severe dizziness, lightheadedness, or headache; severe drowsiness; unusually fast, slow, or irregular heartbeat; vomiting.

Proper storage of Quadratuss:

Store Quadratuss at room temperature, between 59 and 86 degrees F (15 and 30 degrees C). Store away from heat, moisture, and light. Do not store in the bathroom. Keep Quadratuss out of the reach of children and away from pets.

General information:

• If you have any questions about Quadratuss, please talk with your doctor, pharmacist, or other health care provider.


• Quadratuss is to be used only by the patient for whom it is prescribed. Do not share it with other people.


• If your symptoms do not improve or if they become worse, check with your doctor.


• Check with your pharmacist about how to dispose of unused medicine.

This information is a summary only. It does not contain all information about Quadratuss. If you have questions about the medicine you are taking or would like more information, check with your doctor, pharmacist, or other health care provider.

Issue Date: February 1, 2012

Database Edition 12.1.1.002

Copyright © 2012 Wolters Kluwer Health, Inc.

More Quadratuss resources

• Quadratuss Side Effects (in more detail)
• Quadratuss Use in Pregnancy & Breastfeeding
• Quadratuss Drug Interactions
• Quadratuss Support Group
• 0 Reviews for Quadratuss - Add your own review/rating

Compare Quadratuss with other medications

• Cold Symptoms
• Nasal Congestion
• Sinus Symptoms

Quetiapine Sustained-Release Tablets

Pronunciation: kwe-TYE-a-peen
Generic Name: Quetiapine
Brand Name: Seroquel XR

Quetiapine Sustained-Release Tablets are an antipsychotic. It may increase the risk of death when used to treat mental problems caused by dementia in elderly patients. Most of the deaths were linked to heart problems or infection. Quetiapine Sustained-Release Tablets are not approved to treat mental problems caused by dementia.

Antidepressants may increase the risk of suicidal thoughts or actions in children, teenagers, and young adults. However, depression and certain other mental problems may also increase the risk of suicide. Talk with the patient's doctor to be sure that the benefits of using Quetiapine Sustained-Release Tablets outweigh the risks.

Family and caregivers must closely watch patients who take Quetiapine Sustained-Release Tablets. It is important to keep in close contact with the patient's doctor. Tell the doctor right away if the patient has symptoms like worsened depression, suicidal thoughts, or changes in behavior. Discuss any questions with the patient's doctor.

Quetiapine Sustained-Release Tablets are used for:

Treating schizophrenia or bipolar disorder. It is also used to treat depression when used along with other medicines. It may also be used for other conditions as determined by your doctor.

Quetiapine Sustained-Release Tablets are an atypical antipsychotic. Exactly how it works is not known. It affects certain receptors in the brain. This may help to improve symptoms associated with schizophrenia.

Do NOT use Quetiapine Sustained-Release Tablets if:

• you are allergic to any ingredient in Quetiapine Sustained-Release Tablets


• you have low blood potassium or magnesium levels


• you have a history of certain types of irregular heartbeat (eg, QT prolongation, very slow heartbeat)


• you are taking certain antiarrhythmic medicines (eg, amiodarone, procainamide, quinidine, sotalol), certain antipsychotic medicines (eg, ziprasidone), methadone, pentamidine, certain phenothiazines (eg, chlorpromazine, thioridazine), or certain quinolone antibiotics (eg, moxifloxacin)

Contact your doctor or health care provider right away if any of these apply to you.

Video: Treatment for Depression

Treatments for depression are getting better everyday and there are things you can start doing right away.

Before using Quetiapine Sustained-Release Tablets:

Some medical conditions may interact with Quetiapine Sustained-Release Tablets. Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

• if you are pregnant, planning to become pregnant, or are breast-feeding


• if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement


• if you have allergies to medicines, foods, or other substances


• if you or a family member has a history of bipolar disorder (manic depression) or other mental or mood problems, suicidal thoughts or attempts, a certain type of irregular heartbeat (prolonged QT interval), or diabetes or high blood sugar


• if you drink alcohol or have a history of alcohol or substance abuse


• if you have Alzheimer disease, dementia, poor health, or trouble swallowing, or you are very overweight


• if you are dehydrated or have low blood volume


• if you have a history of heart attack or other heart problems (eg, enlargement of the heart, heart failure, irregular heartbeat), stroke, blood vessel problems (eg, in the brain), high blood cholesterol or triglyceride levels, or high or low blood pressure


• if you have a history of low white blood cell levels, including low levels caused by medicine; liver problems; thyroid problems; cataracts; narrow-angle glaucoma; seizures; neuroleptic malignant syndrome (NMS); low blood magnesium or potassium levels; high blood prolactin levels; or breast cancer


• if you take medicines for depression or Parkinson disease


• if you take any medicine that may increase the risk of a certain type of irregular heartbeat (prolonged QT interval). Check with your doctor or pharmacist if you are unsure if any of your medicines may increase the risk of this type of irregular heartbeat

Some MEDICINES MAY INTERACT with Quetiapine Sustained-Release Tablets. Tell your health care provider if you are taking any other medicines, especially any of the following:

• Antiarrhythmic medicines (eg, amiodarone, procainamide, quinidine, sotalol), antipsychotic medicines (eg, ziprasidone), methadone, pentamidine, phenothiazines (eg, chlorpromazine , thioridazine), or quinolone antibiotics (eg, moxifloxacin) because the risk of irregular heartbeat may be increased


• Alpha-blockers (eg, doxazosin) or other medicine for high blood pressure because the risk of low blood pressure and fainting may be increased


• Anticholinergics (eg, scopolamine), azole antifungals (eg, ketoconazole), divalproex or valproic acid, fluvoxamine, macrolide antibiotics (eg, erythromycin), protease inhibitors (eg, ritonavir), or telithromycin because they may increase the risk of Quetiapine Sustained-Release Tablets's side effects


• Barbiturates (eg, phenobarbital), carbamazepine, corticosteroids (eg, prednisone), hydantoins (eg, phenytoin), rifamycins (eg, rifampin), or thioridazine because they may decrease Quetiapine Sustained-Release Tablets's effectiveness


• Dopamine receptor agonists (eg, pramipexole) or levodopa because their effectiveness may be decreased by Quetiapine Sustained-Release Tablets

This may not be a complete list of all interactions that may occur. Ask your health care provider if Quetiapine Sustained-Release Tablets may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

How to use Quetiapine Sustained-Release Tablets:

Use Quetiapine Sustained-Release Tablets as directed by your doctor. Check the label on the medicine for exact dosing instructions.

• Quetiapine Sustained-Release Tablets comes with an extra patient information sheet called a Medication Guide. Read it carefully. Read it again each time you get Quetiapine Sustained-Release Tablets refilled.


• Quetiapine Sustained-Release Tablets are best taken in the evening. Take it by mouth on an empty stomach or with a light meal.


• Swallow Quetiapine Sustained-Release Tablets whole. Do not break, crush, or chew before swallowing.


• Continue to take Quetiapine Sustained-Release Tablets even if you feel well. Do not miss any doses.


• Do not suddenly stop taking Quetiapine Sustained-Release Tablets without first talking with your doctor. You may have an increased risk of side effects. If you need to stop Quetiapine Sustained-Release Tablets, your doctor will gradually lower your dose.


• If you miss a dose of Quetiapine Sustained-Release Tablets, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once. If you miss taking Quetiapine Sustained-Release Tablets for longer than 1 week, contact your doctor before you start to take it again. Your dose may need to be adjusted.

Ask your health care provider any questions you may have about how to use Quetiapine Sustained-Release Tablets.

Important safety information:

• Quetiapine Sustained-Release Tablets may cause drowsiness, dizziness, or blurred vision. These effects may be worse if you take it with alcohol or certain medicines. Use Quetiapine Sustained-Release Tablets with caution. Do not drive or perform other possibly unsafe tasks until you know how you react to it.


• Do not drink alcohol or use medicines that may cause drowsiness (eg, sleep aids, muscle relaxers) while you are using Quetiapine Sustained-Release Tablets; it may add to their effects. Ask your pharmacist if you have questions about which medicines may cause drowsiness.


• Quetiapine Sustained-Release Tablets may cause dizziness, light-headedness, or fainting; alcohol, hot weather, exercise, or fever may increase these effects. This may be more likely to occur when you start to take Quetiapine Sustained-Release Tablets, and also if your dose increases. To prevent these effects, sit up or stand slowly, especially in the morning. Sit or lie down at the first sign of any of these effects.


• Do not drink alcohol while you are using Quetiapine Sustained-Release Tablets.


• Do not become overheated or dehydrated in hot weather or while you are being active; heatstroke, dizziness, or fainting may occur.


• Several weeks may pass before your symptoms improve. Do NOT take more than the recommended dose or use for longer than prescribed without checking with your doctor.


• Children, teenagers, and young adults who take Quetiapine Sustained-Release Tablets may be at increased risk for suicidal thoughts or actions. Watch all patients who take Quetiapine Sustained-Release Tablets closely. Contact the doctor at once if new, worsened, or sudden symptoms, such as depressed mood; anxious, restless, or irritable behavior; panic attacks; or any unusual change in mood or behavior, occur. Contact the doctor right away if any signs of suicidal thoughts or actions occur.


• Quetiapine Sustained-Release Tablets may rarely cause a prolonged, painful erection. This could happen even when you are not having sex. If this is not treated right away, it could lead to permanent sexual problems such as impotence. Contact your doctor right away if this happens.


• Quetiapine Sustained-Release Tablets may raise your blood sugar. High blood sugar may make you feel confused, drowsy, or thirsty. It can also make you flush, breathe faster, or have a fruit-like breath odor. If these symptoms occur, tell your doctor right away.


• Diabetes patients - Check blood sugar levels closely. Ask your doctor before you change the dose of your diabetes medicine.


• NMS is a possibly fatal syndrome that can be caused by Quetiapine Sustained-Release Tablets. Symptoms may include fever; stiff muscles; confusion; abnormal thinking; fast or irregular heartbeat; and sweating. Contact your doctor at once if you have any of these symptoms.


• Some patients who take Quetiapine Sustained-Release Tablets may develop muscle movements that they cannot control. This is more likely to happen in elderly patients, especially women. The chance that this will happen or that it will become permanent is greater in those who take Quetiapine Sustained-Release Tablets in higher doses or for a long time. Muscle problems may also occur after short-term treatment with low doses. Tell your doctor at once if you have muscle problems with your arms; legs; or your tongue, face, mouth, or jaw (eg, chewing movements, mouth puckering, puffing of cheeks, tongue sticking out) while taking Quetiapine Sustained-Release Tablets.


• Rarely, Quetiapine Sustained-Release Tablets may lower the ability of your body to fight infection. Avoid contact with people who have colds or infections. Tell your doctor if you notice signs of infection like fever, sore throat, rash, or chills.


• Quetiapine Sustained-Release Tablets may increase the amount of a certain hormone (prolactin) in your blood. Symptoms may include enlarged breast or decreased sexual ability in men missed menstrual period or nipple discharge in women. Contact your doctor right away if any of these symptoms occur.


• Quetiapine Sustained-Release Tablets may interfere with certain lab tests, including urine drug screen tests. Be sure your doctor and lab personnel know you are taking Quetiapine Sustained-Release Tablets.


• Lab tests, including complete blood cell counts, blood sugar or cholesterol levels, liver function, thyroid function, or eye exams, may be performed while you use Quetiapine Sustained-Release Tablets. You may also receive regular weight checks while you use Quetiapine Sustained-Release Tablets. These tests may be used to monitor your condition or check for side effects. Be sure to keep all doctor and lab appointments.


• Use Quetiapine Sustained-Release Tablets with caution in the ELDERLY; they may be more sensitive to its effects, especially uncontrolled muscle movements.


• Quetiapine Sustained-Release Tablets should be used with extreme caution in CHILDREN younger than 18 years old; safety and effectiveness in these children have not been confirmed. Increased blood pressure has been reported in CHILDREN and TEENAGERS who use Quetiapine Sustained-Release Tablets.


• PREGNANCY and BREAST-FEEDING: If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of taking Quetiapine Sustained-Release Tablets while you are pregnant. Using Quetiapine Sustained-Release Tablets during the third trimester may result in uncontrolled muscle movements or withdrawal symptoms in the newborn. Discuss any questions or concerns with your doctor. Quetiapine Sustained-Release Tablets are found in breast milk. Do not breast-feed while taking Quetiapine Sustained-Release Tablets.

If you stop taking Quetiapine Sustained-Release Tablets suddenly, you may have WITHDRAWAL symptoms. These may include diarrhea, dizziness, headache, irritability, nausea, trouble sleeping, or vomiting.

Possible side effects of Quetiapine Sustained-Release Tablets:

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome:

Constipation; dizziness; drowsiness; dry mouth; increased appetite; joint pain; light-headedness; stomach upset; stuffy nose; tiredness; weight gain.

Seek medical attention right away if any of these SEVERE side effects occur:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); confusion; difficult or painful urination; fainting; fast, slow, or irregular heartbeat; fever, chills, or persistent sore throat; hallucinations; increased saliva production or drooling; increased sweating; memory loss; menstrual changes; muscle pain, stiffness, or weakness; new or worsening mental or mood changes (eg, aggressiveness, agitation, anxiety, depression, exaggerated feeling of well-being, hostility, impulsiveness, inability to sit still, irritability, panic attacks, restlessness); numbness, burning, or tingling; persistent, painful erection; red, swollen, blistered, or peeling skin; seizures; severe or prolonged dizziness, light-headedness, or headache; shortness of breath; suicidal thoughts or actions; swelling of the hands, legs, or feet; symptoms of high blood sugar (eg, increased hunger, thirst, or urination; unusual weakness); tremor; trouble concentrating, speaking, or swallowing; trouble sleeping; trouble walking or standing; uncontrolled muscle movements (eg, arm or leg movements, jerking or twisting, twitching of the face or tongue); vision changes.

This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider. Call your doctor for medical advice about side effects. To report side effects to the appropriate agency, please read the Guide to Reporting Problems to FDA.

See also: Quetiapine side effects (in more detail)

If OVERDOSE is suspected:

Contact 1-800-222-1222 (the American Association of Poison Control Centers), your local poison control center, or emergency room immediately. Symptoms may include fainting; fast or irregular heartbeat; muscle pain, weakness, or cramping; severe dizziness, drowsiness, or light-headedness.

Proper storage of Quetiapine Sustained-Release Tablets:

Store Quetiapine Sustained-Release Tablets at room temperature, between 59 and 86 degrees F (15 and 30 degrees C). Store away from heat, moisture, and light. Do not store in the bathroom. Keep Quetiapine Sustained-Release Tablets out of the reach of children and away from pets.

General information:

• If you have any questions about Quetiapine Sustained-Release Tablets, please talk with your doctor, pharmacist, or other health care provider.


• Quetiapine Sustained-Release Tablets are to be used only by the patient for whom it is prescribed. Do not share it with other people.


• If your symptoms do not improve or if they become worse, check with your doctor.


• Check with your pharmacist about how to dispose of unused medicine.

This information is a summary only. It does not contain all information about Quetiapine Sustained-Release Tablets. If you have questions about the medicine you are taking or would like more information, check with your doctor, pharmacist, or other health care provider.

Issue Date: February 1, 2012

Database Edition 12.1.1.002

Copyright © 2012 Wolters Kluwer Health, Inc.

More Quetiapine resources

• Quetiapine Side Effects (in more detail)
• Quetiapine Use in Pregnancy & Breastfeeding
• Quetiapine Drug Interactions
• Quetiapine Support Group
• 277 Reviews for Quetiapine - Add your own review/rating

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