The document discusses characteristics of antihypertensive drugs including their mechanisms of action. It describes the renin-angiotensin-aldosterone system and how drugs like ACE inhibitors work to inhibit it. It then summarizes different classes of antihypertensive drugs like ACE inhibitors, ARBs, calcium channel blockers, and diuretics; and how they lower blood pressure through various mechanisms such as vasodilation and sodium excretion. Potential side effects and considerations for use are also briefly mentioned.