Verapamil
CALAN
Pronunciation: ver-AP-a-mil
“Very rapid Calcium antagonist”
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.
Verapamil prescription history
Animated chart of estimated U.S. prescriptions per year, Calcium-channel blockers (1981–2026). Verapamil enters in 1981 (estimated).
FDA-approved for
- angina (1981)
- arrhythmias (~1982)
- hypertension (~1986)
Off-label
- cluster headache
Principal riskBradycardia, constipation; a moderate CYP3A4 inhibitor
Classes and tags
Clinical profile
Legacy pregnancy categoryC
Defining liabilityBradycardia, heart block and hypotension; overdose can cause refractory cardiogenic shock.
FDA label
Read the full label on DailyMed ↗
NO BOXED WARNINGS
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Angina (vasospastic, unstable, chronic stable) | Adults | 80–120 mg TID (40 mg TID if increased response expected, e.g., elderly, hepatic impairment) | 80–120 mg TID | 480 mg/day |
| AF/atrial flutter rate control (with digitalis) | Adults | 240–320 mg/day divided TID–QID | 240–320 mg/day divided TID–QID | 480 mg/day |
| PSVT prophylaxis (non-digitalized) | Adults | 240–480 mg/day divided TID–QID | 240–480 mg/day divided TID–QID | 480 mg/day |
| Essential hypertension | Adults | 80 mg TID (40 mg TID in elderly or small stature) | 240–360 mg/day (no added effect shown >360 mg) | 480 mg/day |
Titration Angina: daily (unstable) or weekly intervals, efficacy assessed ~8 h post-dose; hypertension: assess at end of dosing interval
Renal Undefined
Hepatic Decreased hepatic function: 40 mg TID may be warranted
Half-life rises with chronic dosing, so maximal response may be delayed; antiarrhythmic effect evident within first 48 h, antihypertensive within first week.
Available strengths
- tab 40, 80, 120 mg
- DR cap 120, 180, 240, 360 mg
- ER cap 100, 120, 180, 200, 240, 300, 360 mg
- ER tab 120, 180, 240 mg
- inj 2.5 mg/mL
Contraindications
- Severe left ventricular dysfunction
- Hypotension (SBP <90 mmHg) or cardiogenic shock
- Sick sinus syndrome (unless functioning ventricular pacemaker)
- Second- or third-degree AV block (unless functioning ventricular pacemaker)
- Atrial flutter/fibrillation with accessory bypass tract (e.g., WPW, LGL)
Cautions
- Heart failure
- Hypotension
- Elevated liver enzymes — monitor LFTs periodically
- Accessory bypass tract (WPW/LGL)
- Atrioventricular block
- Hypertrophic cardiomyopathy (IHSS)
Adverse reactions
- Constipation (7.3%)
- Dizziness
- Nausea
- Hypotension
- Headache
- Edema
- CHF/pulmonary edema
- Fatigue
- Dyspnea
- Bradycardia (HR <50)
- AV block
- Rash
Cost
| Strength | #/mo | generic $/mo | CostPlus | |
|---|---|---|---|---|
| 40 mg | tab | 30 qd | $3.38 | offered |
| 80 mg | tab | 30 qd | $2.20 | offered |
| 120 mg | tab | 30 qd | $2.66 | offered |
Other forms: Verapamil ER (CALAN SR)
Generic entry1985
Open Verapamil in the interactive console ↗
Memory aids: interaction avatars
Open Verapamil in the interactive console ↗
Self-check
- For which headache is verapamil first-line prevention here?
Cluster headache. - What cardiac effect precludes verapamil in reduced EF?
Negative inotropy.