Which class of anti-hypertensives has a direct intrinsic natriuretic effect at the renal tubules?

The correct choice is the calcium channel blockers. This class of anti-hypertensive agents works primarily by inhibiting calcium ions from entering smooth muscle cells, which leads to relaxation of vascular smooth muscle and vasodilation, effectively lowering blood pressure. Additionally, calcium channel blockers also exhibit a direct effect on the renal tubules by promoting natriuresis, which is the excretion of sodium through urine. This mechanism is beneficial not only for managing hypertension but also for preventing fluid retention and contributing to the overall therapeutic effects.

In contrast, ACE inhibitors primarily work by blocking the conversion of angiotensin I to angiotensin II, which reduces vasoconstriction and fluid retention through the renin-angiotensin-aldosterone system. While they do have diuretic effects, this is secondary to their action on angiotensin II rather than a direct natriuretic effect at the renal tubules.

Beta-blockers mainly work by blocking the effects of adrenaline on beta-adrenergic receptors, which can lead to lower heart rate and reduced cardiac output. They generally do not have a significant direct natriuretic effect on the renal tubules.

Angiotensin receptor blockers (ARBs) block the receptors for angiotensin II