Brand Name: OMNISART
Generic Name: Losartan
Preparations: 25/ 50 mg Tablets
Pharmacological Categories: Antihypertensives, Angiotensin II blocker

Mechanism of Action (MOA)
OMNISART (Losartan) competitively inhibits binding of angiotensin II to AT1 in vascular smooth muscle and adrenal glands and results in inhibition of vasoconstriction and aldosterone secretion. Hence, OMNISART reduces blood pressure by decreasing peripheral resistance and increasing sodium and water excretion while decreasing potassium excretion.

Pharmacokinetics
Absorption: Readily absorbed from the gastrointestinal tract
Bioavailability: About 33%
Metabolism: Liver; active metabolite is carboxylic acid derivative (E-3174)
Peak Plasma Concentration: Losartan: about 1 hour; E-3174: 3 to 4 hours
Protein Binding: More than 98% (both Losartan and E-3174)
Elimination Half-life: About 1.5 to 2.5 hours, E-3174: about 3 to 9 hours
Excretion: Urine and faeces

Indications and Dosage
• Hypertension: 50 mg OD, may be increased if necessary to 100 mg daily as a single dose or in two divided doses.
• Heart Failure (60 years and over): Initially dose of 12.5 mg is given OD and may be doubled at weekly intervals to a usual maintenance dose of 50 mg OD.
• Diabetic nephropathy: 50 mg OD, increased to 100 mg OD daily depending on the blood pressure.

Side Effects
MILD to TRANSIENT: Dizziness, headache, dose-related orthostatic hypotension, hypotension, and impaired renal function
RARE: Rash, urticaria, pruritus, angioedema, and raised liver enzyme values
REPORTED: Hyperkalaemia, myalgia, arthralgia, respiratory tract disorders, back pain, gastrointestinal disturbances, fatigue, and neutropenia
RERELY REPORTED: Rhabdomyolysis

Contraindications
Hypersensitivity, pregnancy, coadministration with aliskiren in patients with diabetes, severe hepatic impairment

Warnings/ Precautions
• Lower doses should be considered in patients with mild or moderate hepatic impairment.
• Caution in patients with renal artery stenosis, volume depletion (e.g. those having high-dose diuretic therapy), and who are at risk of hypotension.
• Serum potassium concentrations should be monitored, especially in the elderly and patients with renal impairment, and potassium-sparing diuretics should be avoided.

Drug Interactions
• The antihypertensive effects may be potentiated by drugs or other agents that lower blood pressure.
• An additive hyperkalaemic effect is possible with potassium supplements, potassium-sparing diuretics, or other drugs that can cause hyperkalaemia.
• NSAIDS should be used with caution, particularly in those who are inadequately hydrated as the risk of renal impairment may be increased; use of NSAID may also attenuate hypotensive effect of losartan.
• Use with ACE inhibitor may increase the risk of hyperkalaemia, hypotension, and syncope, particularly in patients with atherosclerotic disease or heart failure, or in diabetics who have end-organ damage.
• Interactions may occur with drugs that affect cytochrome P450 enzymes.

Pregnancy Category: D; contraindicacted in all trimesters

Presentations
OMNISART 25: 10 X 10’s
OMNISART 50: 10 X 10’s