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CARDIOVASCULAR SYSTEM › CARDIAC THERAPY › ANTIARRHYTHMICS, CLASS I AND III › Antiarrhythmics, class Ia
hydroquinidine
C01BA13
Forms & Strengths
- Oral tablets: 200mg, 300mg
- Parenteral forms: 250mg/mL injection
- Extended-release oral capsules: 200mg, 300mg
Adult Dosing
- Arrhythmias: 200-600mg every 4-6 hours orally
- Ventricular tachycardia: 400-600mg every 2 hours intravenously
- Conversion of atrial fibrillation: 400-600mg orally every 2 hours
Pediatric Dosing
- Infants >1 month and children: 2-4mg/kg every 4-6 hours orally
- Newborns 0-1 month: 1-2mg/kg every 6-8 hours orally and intravenously
Indications
- Ventricular arrhythmias
- Atrial fibrillation
- Paroxysmal supraventricular tachycardia
- Prevention of recurrence of atrial fibrillation
Mechanism of Action
- Class I anti-arrhythmic: membrane-stabilizing effect by blocking sodium channels
- Anti-cholinergic effect: reduction of vagal tone
Contraindications
- Hypersensitivity to quinidine or other cinchona alkaloids
- Complete AV block
- Myasthenia gravis
- Digitalis toxicity
Adverse Reactions
- Gastrointestinal: nausea, vomiting, diarrhea
- Cardiovascular: exacerbation of arrhythmias, hypotension
- Cinchonism: tinnitus, headache, visual disturbances, dizziness
- Hematologic: thrombocytopenia, agranulocytosis, hemolytic anemia
Drug Interactions
- Digitalis: increased risk of digitalis toxicity
- Procainamide, amiodarone: increased risk of QT prolongation
- Beta blockers, calcium channel blockers: potential for additive effects
- Phenytoin: decreased quinidine levels
Curated Content: Needs Vetting Before Put to Clinical Use