Cavazide 300 mg is a combination medication containing Captopril and Hydrochlorothiazide, designed to provide effective management of high blood pressure (hypertension) and heart failure. Captopril, an angiotensin-converting enzyme (ACE) inhibitor, works by dilating blood vessels, reducing blood pressure, and improving heart function. Hydrochlorothiazide, a thiazide diuretic, helps lower blood pressure and reduce fluid retention by promoting the excretion of sodium and water.