Antihypertensive

Headache, hypotension, dizziness, breathlessness, fatigue, muscle cramps, bradycardia, palpitations, flushing, oedema, dyspnoea, dyspepsia, cold extremities. Drowsiness, chestpain & impotence rarely. Hypersensitivity reactions.

Additive effect when used with catecholamine depleting drugs; monitor for hypotension and/or marked bradycardia. If used with clonidine, clonidine withdrawal should occur a few days after withdrawal of the beta-blocker to prevent rebound hypertension; if replacing clonidine by beta-blocker, beta-blocker should be introduced only after clonidine administration has stopped for several days. Concurrent use with prostaglandin synthase inhibiting drugs (e.g. indomethacin) may reduce the hypotensive effects of beta-blockers.

Hypotension, sinus bradycardia, 2nd & 3rd degrees of heart block, cardiogenic shock, overt congestive failure, poor LV function, hypersensitivity to either component, pregnancy.

Atenolol is a cardioselective beta blocker. Amlodipine is a dihydropyridine calcium-channel blocker that blocks the transmembrane influx of calcium ions into vascular smooth muscle and cardiac muscle. Combination of the two drugs results in additive antihypertensive action. Absorption: Amlodipine: Plasma levels peak 6-12 hr after oral admin; absolute bioavailability is estimated to be 64-90%. Atenolol: Absorption is rapid and consistent but incomplete; about 50% of an oral dose is absorbed in the GI tract; plasma levels peak 2-4 hr after oral admin. Distribution: Amlodipine: 93% bound to plasma proteins. Atenolol: 6-16% bound to plasma proteins. Metabolism: Amlodipine: About 90% converted to inactive metabolites hepatically. Atenolol: Little or no hepatic metabolism. Excretion: Amlodipine: 10% of parent compound and 60% of the metabolites are removed in the urine; elimination from the plasma is biphasic with terminal half-life of about 30-50 hr. Atenolol: 50% of the oral dose is removed unchanged in the faeces; absorbed drug is removed mainly via renal elimination; half-life is about 6-7 hr.

Excessive fall of BP may occur in elderly patients. Caution in patients with COPD, thyrotoxicosis, congestive failure, vasospastic angina, hepatic & renal impairment. Caution in diabetic patients as beta-blockers may mask tachycardia occurring with hypoglycaemia. Withdrawal should be gradual. Lactation. Safety and efficacy have not been established in children. Not to be used in untreated phaeochromocytoma.