Grapefruit juice increases
carbamazepine levels by about 40%. A case of possible
carbamazepine toxicity has been seen in a man taking
carbamazepine after he started to eat grapefruit.
The manufacturers advise monitoring levels and adjusting the dose of carbama- zepine as necessary. If monitoring is not practical, or regular intake of grapefruit is not desired, it would seem prudent to avoid grapefruit or
grapefruit juice.