Grapefruit juice interacts with certain enzymes in the intestines, which can cause the body to absorb too much of a medication. It takes only one glass of grapefruit juice to cause this effect, which can last for as long as 24 hours. Medications that can be affected by grapefruit juice include some anti-depressants and anti-anxiety medications, some anti-migraine medications, codeine and tramadol, among others. Pomelo and Seville orange products can have the same effect as grapefruit juice.
More facts about grapefruit juice:
- About 20 percent of Americans drink grapefruit juice at breakfast time.
- Grapefruit juice has been linked to fatal overdoses of two antihistamines, astemizole and terfenadine, but both have been withdrawn from the market.
- Despite the potential for drug interactions, grapefruit does have some good effects. Often called a nutraceutical — or a food that has medicinal value — grapefruit juice might lower the risk of breast cancer, work as an immune booster and help reduce water retention.