hydrochlorothiazide + irbesartan: clinical use

Prescribing considerations

• Correct clinically significant volume or sodium depletion before initiation.
• Review renal and hepatic function, diabetes, gout or hyperuricaemia, systemic lupus erythematosus, renal artery stenosis and ischaemic cardiovascular disease.
• Counsel about photosensitivity, UV protection and reporting suspicious skin lesions; reconsider hydrochlorothiazide after previous non-melanoma skin cancer.
• Not recommended for children or adolescents because safety and efficacy are not established.

Contraindications and cautions

• Hypersensitivity to either active ingredient, an excipient or another sulfonamide-derived substance
• Second or third trimester of pregnancy
• Severe renal impairment
• Refractory hypokalaemia or hypercalcaemia
• Severe hepatic impairment, biliary cirrhosis or cholestasis
• Aliskiren co-administration in patients with diabetes or qualifying renal impairment
• Previous hydrochlorothiazide-associated acute respiratory distress syndrome

Monitoring

• Blood pressure and symptoms of hypotension
• Renal function and serum electrolytes, particularly potassium and sodium
• Blood glucose in diabetes or when symptoms suggest hypoglycaemia
• Urate or gout symptoms where clinically relevant
• Skin for new or changing lesions during longer-term hydrochlorothiazide exposure

Clinical pharmacology

Irbesartan selectively antagonises angiotensin II at AT1 receptors and does not inhibit ACE. Hydrochlorothiazide reduces renal tubular sodium and chloride reabsorption, increasing diuresis. Irbesartan may partly offset thiazide-associated potassium loss, although low or high potassium can still occur.

Formulation and product differences

• The selected product is a peach, oval, film-coated oral tablet.
• It contains lactose and is essentially sodium-free.
• Store in the original package to protect it from moisture.

Tablet

Route: Oral

Strengths: 150 mg + 12.5 mg, 300 mg + 12.5 mg, 300 mg + 25 mg