Betaloc

What is it?

A cardioselective β-blocker, metoprolol tartrate, available as tablets of 2 strengths, as modified-release tablets and in ampoules for injection. Betaloc tablets are white, scored and contain 50mg (marked A/BB) or 100mg (marked A/ME). Also, BETALOC-SA modified-release tablets (Durules�), containing 200mg and marked A/MD. Also, BETALOC INJECTION containing 1mg per ml in 5ml ampoules.

Medical Uses

Heart arrhythmias, angina, maintenance therapy in heart attack, hypertension, additional therapy in thyrotoxicosis, prevention of migraine.

Dosage

All adults only; heart attack, 200mg each day in divided doses; heart arrhythmias, 50mg 2 or 3 times each day increasing to maximum daily dose of 300mg. Angina, 50-100mg twice or three times each day. Hypertension, 50mg twice each day at first increasing to 400mg if required. Thyrotoxicosis, 50mg 4 times each day; migraine prevention, 100mg-200mg each day in divided doses. Betaloc-SA; angina, hypertension: 1 tablet taken in the morning, increasing to 2, if needed; prevention of migraine: 1 tablet taken in the morning. Betaloc injection: early treatment after heart attack; 5mg every 2 minutes by intravenous injection to a maximum of 15mg. Fifteen minutes after final injection, patient is transferred to tablets - 50mg taken every 6 hours for 2 days.

Special Care

Pregnancy, breast-feeding, liver or kidney disease, diabetes, metabolic acidosis, poor cerebral blood supply, history of bronchospasm, those undergoing anaesthesia; patients with weak hearts should be treated with digitalis and diuretics. Drug should be stopped gradually.

Avoid Use

Children, patients with asthma, heart diseases including heart block, heart shock, slow heartbeat rate, heart failure.

Possible Drug and Food Interactions

Cardiac depressants, anaesthetics, reserpine, sedatives, class II calcium antagonists, anti- hypertensives, sympathomimetics, cimetidine, indometacin, ergotamine, class I antiarrhythmic drugs, verapamil, clonidine withdrawal, hypoglycaemics, rifampicin, warfarin, ibuprofen.

Known Side Effects

Sleep disturbance, cold feet and hands, slow heartbeat, fatigue on exercise, wheeziness, heart failure, gastro-intestinal disorders; dry eyes or skin rash (stop use gradually), hair loss, low blood pressure, thrombocytopenia (abnormal decline in blood platelets).