Dosing & Uses
Dosage Forms & Strengths
tablet
- 200mg (as sulfate)
- 300mg (as sulfate)
tablet, extended-release
- 300mg (as sulfate)
- 324mg (as gluconate)
injectable solution
- 80mg/mL (as gluconate) - discontinued from U.S. market
Arrhythmias
Quinidine Sulfate
- Test Dose: 200 mg PO quinidine sulfate several hr before full dosage
- Atrial fibrillation: 300-400 mg PO q6hr
- PSVT: 400-600 mg PO q2-3hr until paroxysm terminated
- Atrial/Ventricular Premature Contractions: 200-300 mg PO q6-8hr
- Maint: 200-400 mg PO q6-8hr or 600 mg of SR PO q8-12hr
- No more than 3-4 g/day
Quinidine Gluconate
- 324-660 mg PO q8-12hr
- Maintenance: 648 mg PO q12hr OR 324-660 mg PO q8hr
- PSVT: 400 - 600 mg PO q2-3hr until paroxysm is terminated
- IV: Usual <5 mg/kg (but may need up to 10 mg/kg) at 0.25 mg/kg/min
Malaria
Quinidine gluconate for injection is no longer available in the U.S.
Quinidine Gluconate
- Regimen I
- Load: 24 mg/kg diluted in 250 mL NS IV infusion over 4 hours
- Maintenance: Follow by 12 mg/kg IV infusion over 4 hours q8hr beginning 8 hr after initiation of loading dose except in patients able to swallow the same doses of quinidine are administered using 300 mg quinidine sulfate tablets
- Regimen II
- Load: 10 mg/kg diluted in 5 mL/kg NS IV over 1-2 hr
- Maintenance: Follow by 0.02 mg/kg/min continuous IV infusion; in patients able to swallow oral quinine is administered every 8 hr to give as much quinine as patient received in quinidine q8hr
- PO regimen: 300 mg quinidine or 650 mg quinine PO q8hr for 3 days (Africa and South America) or 7 days (Southeast Asia) or until parasitemia is reduced to 1%
Dosage Modifications
Hepatic impairment: Not studied
Renal impairment
- CrCl <10 mL/min: Administer 75% of normal dose
- CrCl ≥10 L/min: Dose adjustment not necessary
Pseudobulbar Affect (Off-Label)
Excessive laughing or crying, or involuntary emotional expression affects 20-50% of patients with ALS
30 mg PO bid (administer with dextromethorphan)
Dosage Forms & Strengths
tablet
- 200mg (as sulfate)
- 300mg (as sulfate)
tablet, controlled-release
- 300mg (as sulfate)
- 324mg (as gluconate)
injectable solution
- 80mg/mL
Arrhythmias
Quinidine sulfate: 30 mg/kg/day or 900 mg/m²/day PO given in 5 divided doses OR 15-60 mg/kg/day divided q6hr PO
Test dose: 2 mg/kg PO quinidine sulfate; test dose not to exceed 200 mg
Malaria
Quinidine gluconate for injection is no longer available in the U.S.
Load: 10 mg/kg diluted in 5 mL/kg NS IV over 1-2 hr
Maintenance: Follow by 0.02 mg/kg/min continuous IV infusion; in patients able to swallow oral quinine is administered every 8 hr to give as much quinine as patient received in quinidine q8hr
PO regimen: 650 mg quinine PO q8hr for 3 days (Africa and South America) or 7 days (Southeast Asia) or until parasitemia is reduced to 1%
Interactions
Interaction Checker
No Results
Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor
Adverse Effects
>10%
Diarrhea (35%)
Stomach cramping (22%)
Lightheadedness (15%)
QTc prolongation (modest prolongation common; excessive prolongation rare & indicates toxicity) (>10%)
Anorexia (>10%)
Bitter taste (>10%)
Diarrhea (>10%)
Upper GI distress (>10%)
Nausea (>10%)
Vomiting (>10%)
1-10%
Syncope (1-8%)
Palpitation (7%), new or worsened arrhythmias (proarrhythmic effect),
Headache (7%)
Fatigue (7%)
Angina (6%)
Rash (5%)
Weakness (5%)
Sleep disturbance (3%)
Nervousness (2%)
Tremor (2%)
Incoordination (1%)
Blurred vision
Tinnitus
Wheezing
Frequency Not defined
Hypotension
Hepatotoxicity
Arthralgia
Diplopia
Night blindness
Hypersensitivity reactions (eg, fever, hemolytic/aplastic anemia, respiratory arrest, agranulocytosis)
Systemic lupus erythematosus may occur if taking quinidine for prolonged period of time
Warnings
Black Box Warnings
Antiarrhythmic drugs have not been shown to enhance survival in non-life-threatening ventricular arrhythmias and they may increase mortality. The mortality risk increases with structural heart disease.
Quinidine may increase mortality in treatment of atrial fibrillation or atrial flutter
Contraindications
Hypersensitivity to quinidine or cinchona alkaloids
Absence of atrial activity, aberrant impulses or abnormal rhythm due to escape mechanisms, complete AV block or AV dissociation, digoxin toxicity, wide QRS, history of torsades, long QT syndrome, thrombocytopenia, myasthenia gravis, contraindicated w/pregnancy (neonatal thrombocytopenia) and lactation
Drugs or conditions that prolong QT interval
Cautions
In non-life-threatening ventricular arrhythmias, mortality associated with quinidine was consistently greater than that associated with any of a variety of alternative antiarrhythmics
Acute rheumatic fever, acute thyrotoxicosis, bradycardia, CHF, hypokalemia or hypomagnesemia, hypotension, incomplete AV block, sick sinus syndrome, subacute bacterial endocarditis, syncope, concomitant use of digoxin, liver disease, renal impairment, pregnancy/lactation
Electrolyte imbalances due to severe N/V, diarrhea, eating disorders
IV administration requires continuous cardiac & blood pressure monitoring
Low salt diet may increase blood concentrations
Dose should be adjusted within range to achieve desired therapeutic effects within therapeutic plasma concentration and in absence of toxic SE
Avoid grapefruit juice
Very high dosages may induce abortion in pregnant women due to oxytocic effect
Extended release not recommended in children
Pregnancy & Lactation
Pregnancy
There are no adequate and well-controlled studies in pregnant women
Animal reproductive studies have not been conducted
Lactation
Lactation: crosses into breast milk, use extreme caution (AAP Committee states compatible with nursing)
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Class IA (membrane stabilizing) antiarrhythmic agent; inhibits recovery after repolarization resulting in decreasing myocardial excitability & conduction velocity
Direct membrane depressant that decreases conduction velocity, prolongs refractoriness, decreases automaticity and reduces repolarization abnormalities
Absorption
Bioavailability: Sulfate 70%; gluconate 70-80%
Peak Plasma Time: 2 hr (sulfate); 3-6 hr (gluconate)
Onset: PO: 1-3 hr
Duration: 6-8 hr
Distribution
Vd: 2-3 L/kg (adults); 0.5 L/kg (heart failure)
Protein Bound: 80-88% (adults); 50-70% (newborns)
Metabolism
Metabolism: Liver via hepatic P450 enzyme CYP3A4
Metabolites: 3-hydroxyquinidine and 2-quinidinone (some have antiarrhythmic effects)
Enzymes inhibited: CYP2D6
Elimination
Half-Life: 6-8 hr (adults); 3-4hr (children)
Clearance: 3-5 mL/min/kg (adults); 1-2.5 mL/min/kg (children)
Excretion: Urine (15-25%); feces (5%)
Dialyzable: HD: Yes; PD: No
Administration
Oral Administration
May take with or without food
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Patient Handout
Formulary
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