Which antihypertensive category is considered a third-line option for chronic hypertension?

• A. Direct-acting vasodilators
• B. ACE inhibitors
• C. Thiazide diuretics
• D. Beta blockers

Answer: (A)

Direct-acting vasodilators are a third-line option for chronic hypertension. They work by directly relaxing vascular smooth muscle in the arterioles, which lowers peripheral resistance and reduces blood pressure. Their use is limited by notable side effects—reflex tachycardia, fluid retention, and edema—so they’re typically added only after first-line therapies (such as thiazide diuretics, ACE inhibitors or ARBs, and calcium channel blockers) have not achieved target. To mitigate their activating effects, these drugs are often given in combination with a beta-blocker and a diuretic and are reserved for resistant hypertension or specific situations. This is why they’re categorized as third-line agents. Examples include hydralazine and minoxidil.