Schedule H

Oral, Intravenous

• Tablet (Immediate-release): 40 mg, 80 mg

• Tablet (Sustained-release): 120 mg, 240 mg

• Injection: 2.5 mg/mL in 2 mL ampoule (5 mg per ampoule)

INDICATIONS + DOSING — FOR CLINICIAN USE ONLY

Primary Indications (Approved / Standard in India)

1. Hypertension

Parameter Immediate-Release (IR) Sustained-Release (SR)

Starting dose 80 mg TID 120–240 mg once daily

Titration Increase by 80 mg/day every 7–14 days Increase by 120 mg every 7–14 days

Usual maintenance dose 240–360 mg/day in 3 divided doses 240–360 mg once daily

Maximum dose 480 mg/day 480 mg/day

Clinical Notes:

• SR formulation preferred for chronic hypertension due to better compliance

• IR formulation requires 3 times daily dosing

1. Supraventricular Tachyarrhythmias (PSVT, Atrial Flutter/Fibrillation with Rapid Ventricular Response)

A. Acute Conversion (IV):

Parameter Dose

Starting dose 5–10 mg IV bolus over 2–3 minutes

Titration May repeat 5–10 mg after 15–30 minutes if no response

Maximum dose 20 mg total in acute setting

Administration: Continuous ECG and BP monitoring mandatory during IV use

B. Chronic Rate Control (Oral):

Parameter Dose

Starting dose 120 mg/day in 2–3 divided doses (IR) or 120 mg once daily (SR)

Titration Increase based on heart rate response every 7 days

Usual maintenance dose 240–360 mg/day

Maximum dose 480 mg/day

1. Stable Angina Pectoris (including Variant/Prinzmetal Angina)

Parameter Immediate-Release (IR) Sustained-Release (SR)

Starting dose 80 mg TID 180–240 mg once daily

Titration Increase by 80 mg/day every 7 days Increase by 120 mg every 7–14 days

Usual maintenance dose 240–360 mg/day in divided doses 240–360 mg once daily

Maximum dose 480 mg/day 480 mg/day

Clinical Notes:

• Particularly effective in vasospastic (Prinzmetal) angina

• May be combined with nitrates; avoid combination with beta-blockers unless closely monitored

1. Hypertrophic Obstructive Cardiomyopathy (HOCM)

Parameter Dose

Starting dose 80 mg TID (IR formulation preferred for initial titration)

Titration Increase gradually based on symptom relief and tolerability

Usual maintenance dose 240–320 mg/day in 3 divided doses

Maximum dose 480 mg/day

Clinical Notes:

• Use only IR formulation for precise dose titration

• Monitor for worsening heart failure symptoms

Secondary Indications – Adults (Off-label, if any)

Indication Dose Duration Notes

Cluster Headache Prophylaxis Starting: 240 mg/day in divided doses; Maintenance: 240–360 mg/day Throughout cluster period (weeks to months) OFF-LABEL; Specialist only; Basis: Limited RCT data and Indian neurology practice

PAEDIATRIC DOSING (Specialist Only)

Primary Indications (Approved / Standard in India)

1. Supraventricular Tachycardia — Acute Management (IV)

⚠️ Minimum age: >1 year (CONTRAINDICATED in infants <1 year due to risk of cardiovascular collapse)

Age IV Dose Administration

1–15 years 0.1–0.3 mg/kg (max single dose: 5 mg) Slow IV push over 2–3 minutes

Repeat dose (if needed) Same dose after 30 minutes Max cumulative dose: 10 mg

Safety Monitoring:

• Continuous ECG monitoring mandatory

• Blood pressure monitoring before, during, and after administration

• Resuscitation equipment must be immediately available

• Use only under paediatric cardiologist supervision

1. Hypertension — Chronic Management (Oral)

Parameter Dose

Starting dose 1 mg/kg/day in 2–3 divided doses

Titration Increase gradually every 1–2 weeks based on response

Usual maintenance dose 2–4 mg/kg/day in 2–3 divided doses

Maximum dose 10 mg/kg/day OR 480 mg/day (whichever is lower)

Clinical Notes:

• Not first-line in paediatric hypertension

• Reserved for resistant cases under specialist supervision

• Requires regular cardiac and renal monitoring

Secondary Indications – Paediatric (Off-label, if any)

Not routinely documented in Indian paediatric practice

Age Restriction Statement:

• IV use absolutely contraindicated in infants <1 year

• Oral use in children <1 year only under exceptional circumstances with paediatric cardiologist supervision

Note: Verapamil undergoes extensive hepatic first-pass metabolism; bioavailability significantly increased in hepatic impairment.

• Severe left ventricular dysfunction (ejection fraction <35%)

• Hypotension (systolic BP <90 mmHg)

• Cardiogenic shock

• Sick sinus syndrome (unless permanent pacemaker in situ)

• Second-degree or third-degree AV block (unless permanent pacemaker in situ)

• Atrial fibrillation or flutter in Wolff-Parkinson-White (WPW) syndrome — risk of ventricular fibrillation

• Concurrent intravenous beta-blocker administration

• Age <1 year (IV use) — risk of severe cardiovascular collapse

• Known hypersensitivity to verapamil or excipients

• First-degree AV block — monitor for progression

• Resting bradycardia (heart rate <50 bpm)

• Mild to moderate heart failure — risk of decompensation

• Concomitant oral beta-blocker therapy — increased risk of bradycardia and hypotension

• Concomitant digoxin use — monitor digoxin levels

• Hepatic impairment — reduced metabolism, increased drug exposure

• Renal impairment — potential for drug accumulation with chronic use

• Elderly patients — increased sensitivity to hypotensive and bradycardic effects

• Muscular dystrophy — may worsen muscle weakness

• Myasthenia gravis — use with caution

Parameter Details

Overall safety Limited data; use only if benefit clearly outweighs risk

Risk category Category C equivalent

Preferred alternatives Labetalol, methyldopa for pregnancy-induced hypertension; beta-blockers for arrhythmias

When may be used Refractory supraventricular arrhythmias or hypertension unresponsive to first-line agents; specialist supervision required

Maternal monitoring Blood pressure, heart rate, ECG

Fetal monitoring Regular fetal growth assessment; fetal heart rate monitoring if used chronically

Parameter Details

Compatibility Compatible with breastfeeding

Drug levels in milk Low (approximately 0.1–1% of maternal dose reaches infant)

Preferred alternatives Nifedipine or amlodipine for chronic hypertension if concerned

Infant monitoring Observe for bradycardia, lethargy, poor feeding, and inadequate weight gain

Parameter Recommendation

Starting dose 40 mg TID (IR) or 120 mg once daily (SR); 2.5–5 mg for IV

Titration Slower than in younger adults; extend intervals to 2 weeks

Special risks Increased risk of hypotension, bradycardia, constipation, falls, and dizziness

Monitoring More frequent BP, HR, and ECG monitoring; assess renal function periodically

Interacting Drug Effect Recommendation

IV Beta-blockers Profound bradycardia, AV block, hypotension, asystole Avoid concurrent IV use; separate by several hours

Digoxin Increased serum digoxin levels (30–75% increase) Monitor digoxin levels; reduce digoxin dose by 25–50%

Simvastatin Increased simvastatin exposure via CYP3A4 inhibition — myopathy risk Do not exceed simvastatin 10 mg/day

Lovastatin Similar interaction as simvastatin Do not exceed lovastatin 40 mg/day

Rifampicin Markedly reduced verapamil levels via CYP3A4 induction Avoid combination if possible; alternative CCB may be needed

Ivabradine Additive bradycardia Avoid combination

Dantrolene (IV) Risk of hyperkalaemia and cardiovascular collapse Avoid concurrent use

Disopyramide Additive negative inotropic effect Avoid within 48 hours of each other

Interacting Drug Effect Recommendation

Oral beta-blockers Additive bradycardia and hypotension May use together with caution; monitor HR and BP closely

Antihypertensives (ACEi, ARBs, diuretics) Enhanced hypotensive effect Monitor blood pressure; adjust doses as needed

Amiodarone Increased risk of bradycardia, AV block ECG monitoring; consider dose reduction of both

Carbamazepine Verapamil increases carbamazepine levels Monitor for carbamazepine toxicity (ataxia, nystagmus)

Phenytoin Decreased verapamil levels; reduced effect May need higher verapamil dose

Ciclosporin Increased ciclosporin levels Monitor ciclosporin trough levels and renal function

Tacrolimus Increased tacrolimus levels Monitor tacrolimus levels

Erythromycin/Clarithromycin Increased verapamil levels via CYP3A4 inhibition Monitor for verapamil toxicity

Ketoconazole/Itraconazole Increased verapamil levels Use lower verapamil doses

Theophylline Reduced theophylline clearance Monitor theophylline levels

Lithium Variable effects on lithium levels; neurotoxicity risk Monitor lithium levels and for neurotoxic symptoms

• Constipation (most common, especially in elderly — up to 12%)

• Dizziness

• Headache

• Peripheral oedema

• Nausea

• Fatigue

• Bradycardia

• Flushing

Adverse Effect Clinical Notes

AV block (2nd or 3rd degree) May require discontinuation; temporary or permanent pacing may be needed

Severe bradycardia / Asystole Particularly with IV use or overdose; immediate intervention required

Severe hypotension / Cardiogenic shock More common with IV administration; requires IV fluids, calcium gluconate, vasopressors

Heart failure exacerbation May precipitate or worsen CHF in susceptible patients

Hepatotoxicity Rare; cholestatic or mixed pattern; discontinue if liver enzymes significantly elevated

Gingival hyperplasia Rare; with long-term use

Stevens-Johnson Syndrome Very rare; immediate discontinuation required

Phase Parameters

Baseline ECG (PR interval, rhythm), blood pressure, heart rate, liver function tests, renal function

After initiation / dose change Heart rate and blood pressure within 1 week; repeat ECG if dose significantly increased

During IV administration Continuous ECG, BP monitoring every 5 minutes during infusion and for 30 minutes after

Long-term Periodic ECG (especially in elderly or those with conduction disease); LFTs every 6–12 months; monitor for constipation

• Calaptin (Abbott) — IR tablets, SR tablets, Injection

• Isoptin (Abbott/Viatris) — IR tablets, SR tablets, Injection

• Veramil (Zydus Cadila) — SR and IR tablets

• Paripamil (Intas)

• V-Pam (Lupin)

• Various generic formulations available

• Included in NLEM 2022 (40 mg, 80 mg tablets)

• Price ceiling applicable for NLEM formulations under NPPA

1. SR formulation preferred for chronic use — Better compliance, more stable plasma levels, reduced adverse effects compared to IR

1. Never give IV verapamil to patients on beta-blockers — Risk of fatal bradycardia, asystole, and cardiovascular collapse; oral combination is acceptable with close monitoring

1. Constipation management is crucial — Particularly in elderly; proactive dietary advice (high-fiber diet, adequate fluids) and laxatives if needed; may be dose-limiting

1. Excellent option when beta-blockers contraindicated — Particularly useful for rate control in asthmatics or COPD patients where beta-blockers are problematic

1. Monitor digoxin levels closely — Verapamil inhibits P-glycoprotein and reduces renal clearance of digoxin; expect 30–75% increase in digoxin levels

1. Start low and go slow in elderly — Higher risk of adverse effects; use lower starting doses and extend titration intervals

Verapamil; calcium channel blocker; CCB; non-dihydropyridine; hypertension; supraventricular tachycardia; SVT; PSVT; angina; rate control; HOCM; AV nodal blocker; NLEM India

RxIndia v1.0 — 17 Apr 2025

• CDSCO approved product information

• Indian Pharmacopoeia

• NLEM 2022

• AIIMS Hospital Drug Formulary

• API Textbook of Medicine — Cardiology section

• ICMR Guidelines on Hypertension Management

• IAP Guidelines — Paediatric Cardiology section

• Harrison's Principles of Internal Medicine

• Goodman & Gilman's Pharmacological Basis of Therapeutics (for pharmacokinetics and off-label use)