Final answer:
Sympathetic agonists are not used to treat hypertension because they increase blood pressure, unlike ACE inhibitors, calcium channel blockers, and diuretics which are used to lower it.
Step-by-step explanation:
Hypertension, or high blood pressure, can be treated with several types of medications including ACE inhibitors, calcium channel blockers, and diuretics. These medications work in different ways to decrease blood pressure. ACE inhibitors block the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor that increases blood pressure. Calcium channel blockers prevent calcium from entering cells of the heart and blood vessel walls, thus causing vasodilation and lowering blood pressure. Diuretics help eliminate excess sodium and water from the body, reducing blood volume and pressure.
Conversely, sympathetic agonists would not be used to treat hypertension as they activate the sympathetic nervous system, increasing heart rate and vasoconstriction, hence elevating blood pressure. Therefore, the correct answer to the question of which medication is not used to treat hypertension is D. sympathetic agonists.