Verapamil
Administration
- Type: Calcium channel blocker
- Dosage Forms:
- Routes of Administration: IV, PO
- Common Trade Names:
Adult Dosing
- Atrial fibrillation, paroxysmal SVT
- IV: 5-10mg (0.075-0.15 mg/kg), may give an initial 10mg IV after 30 minutes if inadequate response
- PO: 240-48 mg daily in 3-4 divided doses
- Angina, hypertension: 80-120mg PO 3 times per day
Pediatric Dosing
- Afib/flutter, SVT
- IV 0.1-0.2 (<1yo) or 0.1-0.3 (>1yo) mg/kg. Repeat after 30 minutes if inadequate response
- PO: 4-10 mg/kg/day in 3 divided doses
Special Populations
- Pregnancy Rating: Category C, verapapmil crosses the placenta and can cause adverse fetal effects such as heart block, hypotension, and bradycardia
- Lactation risk: Present in breast milk with relative infant dose of <1% which is considered safe for the infant.
- Renal dosing: Can accumulate causing increased effects, monitor closely and consider lowering dose.
- Hepatic dosing: 20-50% of normal dose
Contraindications
- Allergy to class/drug
- Afib/flutter associated with accessory bypass tract, e.g. WPW, Lown-Ganong-Levine syndrome
- Cardiogenic shock, hypotension, EF <30%
- 2nd or 3rd degree AV block, sick sinus syndrome
Adverse Reactions
Serious
Common
- Hypotension
- Edema
- URI or flu-like symptoms
- Dizziness, headache
- Constipation
Pharmacology
- Half-life: 4-20 hours
- Metabolism: Hepatic- P450 CYP3A4, CYP1A2, CYP2C8, CYP2C9 and CYP2C18
- Excretion: Renal primarily. Not dialyzable
Mechanism of Action
- Inhibits L-type (slow) calcium channels, blocking influx of calcium into myocardial cells
- Reduces systemic vascular resistance, vasodiolates peripheral arteries
Comments
See Also
References
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