how long they have to avoid grapefruit juice if they take certain drugs
Patients often ask how long they have to avoid grapefruit juice if they take certain drugs.
Grapefruit juice can increase the absorption of many drugs... lovastatin, simvastatin, triazolam, diazepam, some calcium blockers, protease inhibitors, etc.
Certain substances in grapefruit inactivate cytochrome P450 3A4 in the gut. Now there's evidence that it can take 3 DAYS or longer for enzyme activity to recover.