VERAPAMIL

Indications & Dose:

Treatment of supraventricular arrhythmias  

• BY MOUTH 

Adult: 40–120 mg 3 times a day 

•  BY SLOW INTRAVENOUS INJECTION

Adult: 5–10 mg, to be given over 2 minutes, preferably with ECG monitoring

• Elderly: 5–10 mg, to be given over 3 minutes, preferably with ECG monitoring

Paroxysmal tachyarrhythmias

• BY SLOW INTRAVENOUS INJECTION

Adult: Initially 5–10 mg, followed by 5 mg after 5–10 minutes if required, to be given over 2 minutes,preferably with ECG monitoring

• Elderly: Initially 5–10 mg, followed by 5 mg after 5–10 minutes if required, to be given over 3 minutes, preferably with ECG monitoring

Angina

• BY MOUTH

Adult: 80–120 mg 3 times a day

Hypertension

• BY MOUTH 

Adult: 240–480 mg daily in 2–3 divided doses

Prophylaxis of cluster headache (initiated under specialist supervision)

• BY MOUTH 

Adult: 240–960 mg daily in 3–4 divided doses

Children Oral: upto 6 years: 40mg 2-3 times/day. 6-12 years: 1-3 tabs. of 40mg, 2-3 times a day (max. 360mg/day). Inj: IV 1-5 years: 2-3mg, 6-14 years: 2.5-5mg, only at the onset. Avg. total dose upto 1.5mg/kg/day.

Contraindications:

Sick, sinus syndrome, 2nd or 3rd degree heart block, hypotension less than 90 mm Hg systolic, cardiogenic shock, severe CHF 

Side Effects:

CNS: Asthenia, dizziness, headache, light-headedness

CV: AV block, bradycardia, CHF, edema, hypotension, palpitations

GI: Constipation, nausea

GU: Nocturia, polyuria

SKIN: Rash

Cautions:

Precautions:

CHF, hypotension, hepatic injury, children, renal disease, concomitant IV β-blocker therapy, cirrhosis, Duchenne’s muscular dystrophy.

Pregnancy & old age: Use with caution, breast milk (approx 25% of maternal serum); compatible with breast feeding

Interaction:

Drugs

Amiodarone: Cardiotoxicity with bradycardia and decreased cardiac output

Barbiturates: Reduced plasma concentrations of verapamil

Benzodiazepines: Marked increase in midaizolam concentrations, increased sedation likely to result

Beta-blockers: β-blocker serum concentrations increased (atenolol, metoprolol, propranolol); increased risk of bradycardia, hypotension, AV conduction, and myocardial contractility

Carbamazepine: Increased carbamazepine toxicity when verapamil added to chronic anticonvulsant regimens; reduced metabolism

Cimetidine: Increased verapamil concentrations and effect by cimetidine

Cyclosporine, tacrolirnus: Increased concentrations of these drugs, nephrotoxicity possible

Dantrolene: Hyperkalemia and myocardial depression may occur; consider a dihydropyridine calcium blocker

Diclofenac: Reduced verapamil concentrations

Digitalis glycosides: Increased digoxin concentrations by approximately 70%

Doxazosin, prazosin, terazosin: Enhanced hypotensive effects

Doxarubicin: Increased doxorubicin concentration

Encainide: Increased encainide concentrations

Ethanol: Increased ethanol concentrations, prolongs and increased levels of intoxication

Fentanyl: Severn hypotension or increased fluid volume requirements

Histamine H2-antagonists: Increased blood levels of verapamil with cimetidine

Hydantoins: Serum verapamil levels may fall if used concurrently

Imipramine: Increased imipramine concentrations

Lithium: Potential for neurotoxicity

Neuromuscular blocking agents: Prolonged neuromuscular blockade

Quinidine: Quinidine toxicity via inhibition of metabolism

Rifampin, rifabutin: Induced metabolism; reduced verapamil concentrations

Sulfinpyrazone: Increased clearance of verapamil

Theophylline: Verapamil inhibits metabolism, increases theophylline levels

Vitamin D: Therapeutic efficacy of verapamil may be reduced.

Warnings:

Adverse Effects:

Lactations:

Special Precautions:

Counselling:

Side Effects Or Adverse Reactions:

Patient And Carer Advice: