Grapefruit juice should be avoided with which antihypertensive class due to an interaction?

• A. Calcium channel blockers
• B. ACE inhibitors
• C. ARBs
• D. Beta blockers

Answer: (A)

Grapefruit juice can markedly increase the levels of drugs that are broken down by intestinal CYP3A4 enzymes. The main idea here is that some calcium channel blockers are substrates of CYP3A4, so when grapefruit blocks this enzyme in the gut, more of the drug enters the bloodstream. That leads to stronger blood vessel dilation and a higher risk of dangerous drops in blood pressure, dizziness, or edema. Among antihypertensives, calcium channel blockers fit this interaction profile, especially the dihydropyridine type (like nifedipine and felodipine), which is why grapefruit juice should be avoided with this class. Other antihypertensives such as ACE inhibitors, ARBs, and beta blockers are not notably affected by grapefruit juice in the same way, so they don’t have the same heightened interaction.