Clinical findings have shown that when a patient with hyperlipidemia takes one tablet of Mevastatin with a glass of grapefruit juice, the lipid-lowering effect is equivalent to taking 12 to 15 tablets of the same medication with water. This can lead to muscle pain and even kidney damage. Some patients taking the antihistamine terfenadine may experience dizziness, palpitations, arrhythmia, and in severe cases, sudden death if they consume grapefruit or grapefruit juice during their treatment.
Other medications that can have adverse interactions with grapefruit include cyclosporine, caffeine, calcium channel blockers, and cisapride. The potential for an interaction with medication can last for 24 hours after drinking a glass of grapefruit juice. Therefore, patients taking medication, especially the elderly, should avoid eating grapefruit or drinking grapefruit juice.