I just picked up my prescription for lovastatin. My pharmacist warned me not to drink grapefruit juice while taking this medication. Why? Can I drink orange juice instead?
The grapefruit juice warning is real and should be heeded! The food-drug interactions with grapefruit juice result in more of the active medication getting into your system. In the case of lovastatin and grapefruit juice, taking the two together can provide an amount of lovastatin to your body that is equivalent to consuming 15 doses of lovastatin without grapefruit juice. This can result in significant toxicity.
Many medications undergo this interaction, including some over-the-counter medications like dextromethorphan (found in Robitussin). Some grapefruit juice-drug interactions are worse than others and not all people respond in the same fashion. Also, there are differences in the interaction between different types of grapefruit juice.
However, if the medication label or the pharmacist recommends "do not take with grapefruit juice" then you shouldn't. Except for Seville or bitter orange juice, which is a specialty item not commonly consumed in the U.S., regular orange juice does not cause this interaction and is fine.