The side effects of grapefruit juice

It’s long been known that medications can interact with one another in adverse ways. These interactions are generally listed on a drug’s package insert. But what many people don’t realize is that certain foods can also have an impact on a drug’s effectiveness. Research on such interactions is still in its early stages, but it’s long been known that grapefruit juice can adversely affect a drug’s effectiveness. Grapefruit and grapefruit juice is known to interact with many drugs, often by increasing the concentration of the active ingredient. Studies have shown that grapefruit slows drug metabolism, which raises the blood serum concentration of the drug’s active ingredients.

Currently about 100 drugs are known to interact with grapefruit and grapefruit juice, including pain relievers, sleep aids, drugs to treat high blood pressure (such as beta blockers) as well as antihistamines used to treat allergy symptoms. Current research has also documented an adverse interaction with oral contraceptives, causing an increase in blood serum levels of estradiol, a form of estrogen used in oral contraceptives. This can increase side effects such as breast tenderness as well as increase the risk of thrombosis.

Drug package inserts don’t include warnings about adverse interactions with foods – even though in the case of grapefruit, this information can be crucially important. To reduce risk of adverse reactions, it’s best to swallow tablets with water.