Antihypertensives are drugs commonly prescribed to help lower blood pressure when appropriate diet and regular physical activity alone have not succeeded. They do this by helping relax and expand (dilate) blood vessels, allowing blood to flow more easily or by acting on the kidneys to help increase urination. Some of the more common antihypertensives include diuretics, angiotensin-converting enzyme (ACE) inhibitors, angiotensin-2 receptor antagonists, beta-blockers and calcium channel blockers. Some of these drugs may also be prescribed for heart failure and arrhythmia patients.