The three anti-arrhythmic drugs in common use are amiodarone, disopyramide, flecainide. They are used to manage cardiac arrhythmias, such as atrial fibrillation (AF), atrial flutter and ventricular fibrillation.

Dosage regimen

* Anti-arrhythmics are usually taken two to three times a day.

Patient's knowledge of the medicine's use

* Explain to patients that anti-arrhythmics normalise the cardiac rhythm, as understaind what the medicine does may make them more likely to comply with treatment.

Is the medicine working?

* Has the patient been taking the correct dosage of their medication?

* Has the patients symptoms/condition deteriorated? If so, refer back to the prescriber.

* Is the patient taking any OTC/herbal remedies, which may interact with their medication?

Side effects

* Amiodarone can cause taste disturbances, nausea and vomiting, bradycardia and liver or thyroid problems. Visual disturbances can also occur and should be reported immediately. Amiodarone can also cause photosensitivity reactions, so patients should be advised on the need to use sunscreen during treatment.

* Disopyramide can cause tachycardia and hypotension. It has antimuscarinic activity so can cause dry mouth, blurred vision and urinary retention and may precipitate glaucoma.

* Flecainide commonly causes nausea and vomiting, and can cause dyspnoea and visual disturbances.

Monitoring

* Amiodarone: Liver and thyroid function tests should be performed before commencing treatment and at six monthly intervals. Serum potassium and a chest X-ray should also be taken before starting amiodarone.

* Disopyramide: Blood pressure and cardiac rhythm should be carefully monitored.

* Flecainide can cause serious arrhythmias so cardiac function should be monitored.

Lifestyle

* General "healthy heart" measures should be adopted, such as stopping smoking, losing weight, eating a diet low in fat and salt, taking regular exercise, avoiding stress and caffeine and reducing alcohol intake.

* Patients should be advised that they may be eligible for a "one-off" pneumococcal vaccination and a yearly flu vaccination.

Ken Wan, pharmacist, Clacton-on-Sea, Essex / AF

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