Cimetidine, Phenobarbital, Potassium sparing diuretics, Potassium supplements, Catecholamine depleting drugs, Calcium channel blockers Beta blockers

Essential hypertension

Diarrhea, dyspepsia Muscle cramps,myalgia, back pain Dizziness, insomnia, fatigue, nausea Nasal congestion, ciough, upper respiratory infection, sinus disorder Bradycardia, postural hypertension,

Patients with hypersentivity to losartan and atenolol Pregnancy Heart block greater than first degree Carrdiogenic shock and overt cardiac failure

Special precautions and warnings Lactation Patients with /without history of cardiac failure Impaired renal function Carcinogenesis, mutagenesis and impairment of fertility Bronchospastic disease Anesthesia and major surgery Diabetes and hypoglycemia

Essential hypertension

Dosage

Recommended dose- one tablet once daily Treatment should be initiated with a lower dose and the dosage gradually increased till a maximum of response is observed A Lower dosage should be considered in elderly patients and in patients with hepatic and renal impairment

Pharmacolgy

Losartan Potassium is orally bioavailable, long acting non-peptide angiotensin typpe II receptor antagonist. Losartan and its principal metabolite block the vasoconstrictor andaldosterone-secreting effects of angiotensin II by selecting blocking the binding of angiotensin II to AT1 receptor found in many tissues(eg vascular smooth muscle, adrenal gland) Atenolol is beta 1a cardio selective receptor blocking agent without membrane stabilizing or intrinsic sympathomimetic (partial agonist) activities. Several possible mechanisms of action have been proposed for atenolol and include- compettitive antagonism of catecholamines at peripheral (especially cardiac ) adrenergic neuron sites,leading to decresed cardiac output, a central effect leading to sympathtic outflow to the periphery, suppression of renin activity.

Pharmacokinetics

On oral administration losartan is absorbed from the gastrointestinal tract and its bioavailability is about 50%. It undergoes first pass metabolism to form active carboxylic and metabolite that has greater pharmacological activity than losartan. When administred orally 4% of the dose is excreted unchanged in the urine and 6% is excreted in urine as active metabolite. The elimination half life of losartan and its metabolite are about 2 and 6 hours respy. On oral administration of atenolol 50% of is absorbed from the gastrointestinal tract, the remainder being excreted unchanged in the feces.It undergoes little or no metabolism by the liver and the absorbed portion is eliminated primarily by renal excretion. The elimination half-life of oral atenolol is approx 6 to 7 hrs.