Which beverage increases the effect of certain antihypertensives such as beta-blockers, clonidine, and hydralazine?

Which beverage increases the effect of certain antihypertensives such as beta-blockers, clonidine, and hydralazine?

• A. Grapefruit juice
• B. Orange juice
• C. Apple juice
• D. Milk

Answer: (A)

Grapefruit juice can raise the blood levels of certain antihypertensive drugs by altering how they are absorbed and metabolized in the gut. The juice contains compounds that strongly inhibit intestinal enzymes, especially CYP3A4, and also affect transport proteins like P-glycoprotein. When these pathways are blocked, the drug that would normally be partly broken down before reaching the bloodstream ends up with higher bioavailability and a greater overall effect. This is why grapefruit juice can enhance the effect of some antihypertensives, including drugs in the beta-blocker family, clonidine, and hydralazine. The result is a greater blood pressure-lowering action and a higher risk of side effects such as dizziness or fainting, particularly in older adults who may have slower drug clearance or take multiple meds. The other beverages listed do not have this strong intestinal enzyme-inhibition effect, so they don’t significantly increase the antihypertensive drugs’ plasma levels in the same way. If you’re taking these medications, it’s important to discuss grapefruit juice with a clinician and monitor for signs of excessive hypotension.

Grapefruit juice can raise the blood levels of certain antihypertensive drugs by altering how they are absorbed and metabolized in the gut. The juice contains compounds that strongly inhibit intestinal enzymes, especially CYP3A4, and also affect transport proteins like P-glycoprotein. When these pathways are blocked, the drug that would normally be partly broken down before reaching the bloodstream ends up with higher bioavailability and a greater overall effect.

This is why grapefruit juice can enhance the effect of some antihypertensives, including drugs in the beta-blocker family, clonidine, and hydralazine. The result is a greater blood pressure-lowering action and a higher risk of side effects such as dizziness or fainting, particularly in older adults who may have slower drug clearance or take multiple meds.

The other beverages listed do not have this strong intestinal enzyme-inhibition effect, so they don’t significantly increase the antihypertensive drugs’ plasma levels in the same way. If you’re taking these medications, it’s important to discuss grapefruit juice with a clinician and monitor for signs of excessive hypotension.