Which food item should be avoided with carbamazepine?

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

Answer: (B)

Grapefruit juice can inhibit the enzymes (CYP3A4) and transporters in the gut that normally limit how much carbamazepine gets into your bloodstream. When this inhibition happens, more carbamazepine is absorbed, pushing its level higher in the body. Since carbamazepine has a narrow therapeutic range, even a modest increase can raise the risk of side effects like dizziness, drowsiness, trouble with balance, blurred vision, and potentially more serious toxicity. The other foods listed don’t have a meaningful interaction with carbamazepine, so grapefruit is the one to avoid.