Indication For management of Hypertension
Mechanism of Action

Olmesartan is a selective and competitive angiotensin II Type 1 (AT1) receptor antagonist that blocks the vasoconstrictor and aldosterone-secreting effects of angiotensin II. As a result, Olmesartan relaxes blood vessels, hence lowering BP and increases blood supply and oxygen to the heart.

Hydrochlorothiazide inhibits the reabsorption of Na and chloride in the distal tubules causing increased excretion of Na and water K and hydrogen ions.



Absorption: Bioavailability: Approx. 26%. Time to peak plasma concentration: Approx. 1-2 hr.

Distribution: Volume of distribution: 17 L. Plasma protein binding: ≤99%.

Metabolism: Olmesartan medoxomil undergoes ester hydrolysis in the GI tract to active form Olmesartan.

Excretion: Via faeces (50-65%) and urine (35-50%) both as Olmesartan. Terminal half-life: Approx. 10-15 hr.


Absorption: Rapid absorption from the GI tract. Food decreases rate and extent of absorption.

Time to peak plasma concentration: Approx. 4 hr.

Bioavailability: Approx. 65-70%.

Distribution: Crosses the placenta and distributed in breast milk.

Volume of distribution: 3.6-7.8 L/kg. Plasma protein binding: Approx. 40-68%.

Metabolism: Not metabolised

Excretion: Via urine as unchanged drug.

Plasma half-life: Approx. 5-15 hr.

Side effects


Potentially Fatal: Acute renal failure.

May cause sprue-like enteropathy (Symptoms: Severe, chronic diarrhoea with substantial wt. loss). Dizziness, headache, abdominal pain, dyspepsia, diarrhoea, gastroenteritis, nausea, bronchitis, pharyngitis, rhinitis, arthritis, back pain, skeletal pain, fatigue, flu-like symptoms, angioedema, peripheral oedema, haematuria, UTI, hyperkalaemia, hypertriglyceridemia, hyperuricaemia, hyperglycaemia, elevated liver enzymes.


Electrolyte disturbances, weakness, hypotension, pancreatitis, jaundice, diarrhoea, vomiting, sialadenitis, cramping, constipation, gastric irritation, nausea, anorexia, aplastic anaemia, agranulocytosis, leukopenia, haemolytic anaemia, thrombocytopenia, anaphylactic reactions, necrotising angiitis, resp distress, photosensitivity, fever, urticaria, rash, purpura, hyperglycaemia, glycosuria, hyperuricaemia., muscle spasm, vertigo, paraesthesias, dizziness, headache, restlessness, renal failure, renal dysfunction, interstitial nephritis, erythema multiform, exfoliative dermatitis, alopecia, transient blurred vision, xanthopsia, impotence.


Patients with aortic or mitral valve stenosis, renal artery stenosis; at risk for hypotension (e.g. patients with volume or salt depletion); history of angioedema; at risk for hyperkalaemia (e.g. patients w/ DM). Severe renal and hepatic impairment. Lactation. Monitoring Parameters Monitor BP, serum creatinine and K levels periodically.



Adult: Initial: 10-20 mg once daily may then be increased up to max 40 mg once daily if needed.

Child: 6-16 yr. 35 kg: 10 mg once daily; ≥35 kg: 20 mg once daily. Doses may be doubled once if necessary after 2 wk.

Elderly: No dosage adjustment needed.

Renal impairment: Mild to moderate (Circle: 20-60 mL/min): Max: 20 mg once daily.

Hepatic impairment:

Moderate: Initial: 10 mg once daily may increase up to max 20 mg once daily.


Adult: Initially, 12.5 mg, may increase to 25-50 mg once daily as necessary either alone or w/ other antihypertensives.

Child::6 mth 1-3 mg/kg/day in 1-2 divided doses. Max: 37.5 mg daily; 6 mth to 2 yr 1-2 mg/kg/day in 1-2 divided doses. Max: 37.5 mg daily; >2-12 yr 1-2 mg/kg/day in 1-2 divided doses Max: 100 mg daily.

Elderly: 12.5-25 mg once daily, titrate as necessary in increments of 12.5 mg.

Renal impairm

ent: Severe: Contraindicated.