Verapamil
CALAN
What it isNon-dihydropyridine calcium channel blocker; rate control, angina, and cluster headache prophylaxis.
Why this oneThe strongest AV nodal effect of the calcium channel blockers, and it is first-line for cluster headache prevention.
What limits itNegative inotropy precludes use in reduced EF, and constipation limits treatment. CYP3A4 and P-gp inhibition raises digoxin and susceptible statins.
FDA-approved for
- angina (1981)
- arrhythmias (~1982)
- hypertension (~1986)
Off-label
- cluster headache
FDA label
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| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Essential hypertension | adult | 180 mg QAM (120 mg in elderly/small patients) | 180-480 mg/day | 480 mg/day |
Titration Titrate upward weekly, assessed ~24 h after previous dose
Renal Undefined
Hepatic Undefined
Instructions
- Administer with food
- Swallow whole (extended-release)
Contraindications
- Severe left ventricular dysfunction
- Hypotension (SBP <90 mmHg) or cardiogenic shock
- Sick sinus syndrome (unless functioning pacemaker)
- Second- or third-degree AV block (unless functioning pacemaker)
- Atrial flutter/fibrillation with accessory bypass tract (e.g., WPW, LGL)
Cautions
- Heart failure
- Hypotension
- AV block / bradycardia
- Elevated liver enzymes (per WARNINGS)
Adverse reactions
- Constipation
- Dizziness
- Nausea
- Hypotension
- Headache
- Edema
- Bradycardia
- AV block
- Fatigue
Pregnancy Use only if clearly needed; crosses placenta
Lactation Undefined
NO BOXED WARNINGS
Principal riskBradycardia, constipation; a moderate CYP3A4 inhibitor
Cost, est. cash$20–$1,500/dose or month
Generic entry1985
Classes and tags
Clinical profile
Legacy pregnancy categoryC
Defining liabilityBradycardia, heart block and hypotension; overdose can cause refractory cardiogenic shock.
Mechanism of action: Verapamil ballicule
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