Hypertension is defined as blood pressure above 140/90 mmHg. It can be essential (95% of cases, no identifiable cause) or secondary (5% of cases, due to an underlying condition like kidney disease). Lifestyle modifications like weight loss, reduced salt intake, exercise, and moderation of alcohol can help control hypertension. If lifestyle changes are not enough, medications may be prescribed. Common classes of medications include diuretics, beta-blockers, ACE inhibitors, calcium channel blockers, and ARBs, which work to lower blood pressure by different mechanisms like reducing fluid volume or relaxing blood vessels. Controlling high blood pressure helps prevent damage to organs like the heart, brain, and kidneys that can