Captopril is primarily used in the treatment of high blood pressure (hypertension), helping to relax blood vessels and improve blood flow. It is also effective in managing heart failure by reducing the workload on the heart and improving its efficiency. Additionally, it is prescribed after heart attacks to enhance survival rates and prevent further heart damage. Captopril is sometimes used in diabetic patients to protect kidney function and slow the progression of kidney disease. It works by inhibiting an enzyme that narrows blood vessels, thereby aiding in better circulation and reduced strain on the cardiovascular system.