Avalide is a medication in tablet form that comprises of hydrochlorothiazide and irbesartan as its two primary active ingredients. Hydrochlorothiazide is a type of thiazide diuretic that functions by reducing the absorption of excess salt in the body, which can lead to water retention. On the other hand, irbesartan is an angiotensin II receptor antagonist that helps in widening the blood vessels, lowering blood pressure, and enhancing blood flow. Avalide is prescribed for individuals with high blood pressure.