Both grapefruit and grapefruit juice may interfere with the metabolism of certain medications. The most common result is higher than expected levels of the medication in the body. These increased levels can result in dangerous side effects.
The effect of grapefruit products on the metabolism of certain medications can last for more than 24 hours, so taking the medication at another time is not advised. The best way to avoid the dangerous effects of grapefruit products is to avoid the products altogether when taking medications affected by grapefruit products.
Be sure to discuss any concerns about combining grapefruit products with medications you may be taking with your pharmacist and physician.