irbesartan: clinical use

Prescribing considerations

• Correct volume or sodium depletion before initiation because symptomatic hypotension may occur.
• Use particular caution with renovascular disease, renal impairment, severe heart failure, haemodynamically significant valve disease or obstructive hypertrophic cardiomyopathy.
• Irbesartan is not recommended for primary aldosteronism; experience in severe hepatic impairment is lacking.
• Safety and efficacy have not been established for children and adolescents.

Contraindications and cautions

• Hypersensitivity to irbesartan or a formulation excipient.
• Second or third trimester of pregnancy.
• Concomitant aliskiren in patients with diabetes or renal impairment below the product-specified GFR threshold.

Monitoring

• Check blood pressure, renal function, potassium and sodium before treatment.
• Repeat renal function and electrolytes after initiation or treatment changes, and when acute illness may compromise renal function.
• Continue periodic monitoring once stable, more frequently with kidney disease, diabetes, older age, hyperkalaemia risk or relevant interacting medicines.
• Consider blood-glucose monitoring in diabetes; monitor lithium concentrations if concurrent use is unavoidable.

Clinical pharmacology

Irbesartan is an orally active, selective AT1-receptor antagonist that does not inhibit ACE or require metabolic activation. It is highly protein bound, metabolised mainly through CYP2C9 and glucuronidation, and eliminated through biliary and renal routes; haemodialysis does not remove it.

Formulation and product differences

• The selected product is an uncoated, round white to off-white tablet.
• It contains lactose monohydrate and is essentially sodium-free; excipients can differ between manufacturers.
• Available pack types include blisters and high-count bottles, although not all pack sizes are marketed.

Tablet

Route: Oral

Strengths: 75 mg, 150 mg, 300 mg