Verapamil

Please note: these are basic guidelines, refer to your doctor for a professional medical opinion.

Popular brand names:

Isoptin

Popular combinations:

Tarka

Drug group:

Anti-angina drug, anti-arrhythmic drug, and antihypertensive drug

Prescription needed?

Yes

What does it do?

Verapamil is used in the treatment of:

• Hypertension
• Abnormal heart rhythms – intravenous forms available
• Angina - reduces the frequency of angina attacks but does not relieve pain in an acute attack

How does it work?

Verapamil is a calcium channel blocker – it interferes with the conduction of signals in the muscles of the heart and blood vessels.

Verapamil increases the ability to tolerate physical exertion and can be used safely by asthmatics.

How should it be used?

Avoid grapefruit juice - may increase blood levels of verapamil

What is the typical dosage?

Your doctor will recommend a dosage tailored to your need, but typically:

• Total daily dose for adults: 120–480mg daily
• Taken 2–3 x daily (tablets/liquid) or 1–2 x daily (SR tablets/capsules)

How quickly will it start to work? 

Tablets 1–2 hours;  injection 2–3 minutes 
           

How long will the effects last?

Usually 6–8 hours, SR tablets 12–24 hours  
              

When should I stop using it?

Do not stop the drug without consulting your doctor      
                           

Is it safe for prolonged use?

No problems expected. Rarely, long-term use can lead to  gynaecomastia (breast enlargement in men) or enlargement of the gum tissues.                     

What are the possible side effects?

The following have been reported:

• More common: constipation, headache, nausea, vomiting, ankle swelling
• Less common: dizziness, rash, breast enlargement in males, increase in gum tissue
• Report to your doctor before taking your next dose if you experience: any severe side effects

What other considerations are important?

Dosage may be adjusted by your doctor under certain conditions.

• Certain health problems: liver problems, heart failure, porphyria
• Other medicines: beta blockers, carbamazepine, ciclosporin, digoxin, theophylline, sirolimus, ivabradine, rifampicin, barbiturates, clarithromycin/erythromycin, simvastatin/atorvastatin, colchicine
• Pregnancy and breast-feeding: Not usually prescribed in pregnancy, normal doses are unlikely to affect the breastfed baby
• Children: Reduced dose necessary
• Over 60: No special problems
• Driving and hazardous work: Caution, the drug can cause dizziness
• Alcohol: Avoid, may further reduce blood pressure and cause dizziness
• Surgery and general anaesthetics: Drug may need to be stopped before surgery