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CARDIOVASCULAR SYSTEM › CARDIAC THERAPY › ANTIARRHYTHMICS, CLASS I AND III › Antiarrhythmics, class Ia
sparteine
C01BA04
Forms & Strengths
- Oral tablet: 50 mg
- Solution for injection: 100 mg/2 mL
Adult Dosing
- Arrhythmias: 50 to 100 mg orally 3 to 4 times daily
- Obstetric use (historical): 100 to 200 mg intramuscularly, repeated as needed for labor induction
Pediatric Dosing
- Safety and efficacy not established in pediatric patients; use is generally avoided
Indications
- Treatment of cardiac arrhythmias (historical/outdated)
- Oxytocic agent for induction of labor (obsolete practice)
Mechanism of Action
- Class IA antiarrhythmic agent with local anesthetic properties
- Direct depressant action on the myocardium, slowing conduction velocity and prolonging refractory period
- Oxytocic effect via direct stimulation of uterine smooth muscle
Contraindications
- Known hypersensitivity to sparteine
- High-degree atrioventricular block without a functioning pacemaker
- Severe myocardial depression or heart failure
- Obstetric contraindications including cephalopelvic disproportion and fetal distress
Adverse Reactions
- Hypotension and bradycardia
- Nausea, vomiting, and gastrointestinal upset
- Dizziness, vertigo, and headache
- Uterine tetany and potential fetal distress (when used in obstetrics)
Drug Interactions
- Additive myocardial depression with other antiarrhythmic agents (e.g., quinidine, procainamide)
- Enhanced hypotensive effects when co-administered with antihypertensives or general anesthetics
- Potential pharmacokinetic interactions via CYP2D6 inhibition (sparteine is a classic CYP2D6 probe substrate)
Curated Content: Needs Vetting Before Put to Clinical Use