Definition: Antihypertensive means "low blood pressure" or "no high blood pressure." Detailed, it's a medication designed to lower blood pressure in patients with hypertension (high blood pressure). The specific chemical compound used is a potassium channel blocker or an alpha-blocker, often with other drugs or herbs like ginkgo biloba. It works by relaxing the smooth muscle cells in the arteries, causing blood flow and lowering heart rate.