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Answer:Some prescription medications may interact with grapefruit juice. Various chemical processes help break down medications within the body, and studies have found that grapefruit juice and whole grapefruit block a specific enzyme in the liver and the small intestines. Only medications that are metabolized by this enzyme will be affected by grapefruit juice. The result of the interaction is higher-than-normal blood levels of the medication and potential adverse effects. The increases in blood levels of the medication may continue 24 hours after consuming grapefruit juice.

Medications affected by this interaction include certain calcium channel blockers (for example, nifedipine), benzodiazepines (including alprazolam and diazepam), some cholesterol-lowering medications in the statin family (such as lovastatin and simvastatin), and medications used to suppress the immune system (for example, cyclosporine).

Note that tangelos and Seville oranges and their juice may have a similar effect as grapefruit.

Over-the-counter medications are not affected by grapefruit or grapefruit juice.

Check with your doctor or pharmacist to find out if the prescription drug you take may interact with grapefruit juice, or to find out if a noninteracting medication is available to treat your condition.

Find more information about statin drugs in our Health Library.

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