Sodium nitroprusside has potent vasodilating effects in arterioles and venules (arterioles more than venules, but this selectivity is much less marked than that of nitroglycerin, which acts preferentially at venous smooth muscle) as a result of its breakdown to nitric oxide (NO).[5][6][7] It is intravenously infused in cases of acute hypertensive crises.[5][8] Its therapeutic effects are usually seen within a few minutes.[1]