Hydralazine's effect on blood pressure and heart rate?

• A. Decreases BP and decreases HR
• B. Increases BP and increases HR
• C. Decreases BP; heart rate stays about normal
• D. No effect on BP or HR

Answer: (C)

Hydralazine lowers blood pressure by directly dilating arterioles, which reduces systemic vascular resistance and thus lowers arterial pressure. The heart rate is not typically reduced by this drug; in fact, the body may compensate to maintain perfusion, so the heart rate tends to stay around normal rather than decrease. So the best description is a drop in BP with the heart rate remaining about normal. (The other options either claim no BP change, an increase in BP, or a decrease in HR, which don’t fit hydralazine’s arterial vasodilating action and typical reflex responses.)