The effects of some medications can be increased or decreased when they are taken with certain foods. Although grapefruit juice interacts with many medications, it does not affect beta blockers. However, because beta blockers can be affected by some foods and over-the-counter medications, if you are taking beta blockers you should talk to your doctor about food and drug interactions.
Grapefruit juice can interfere with how the body breaks down and eliminates medications. Many medications are broken down by the liver using an enzyme called cytochrome P450, which is inhibited by grapefruit juice. Consequently, grapefruit juice can increase the levels of many drugs in the body, including several cholesterol-lowering statins. However, grapefruit juice does not interfere with the metabolism of beta blockers.
Beta blockers include the drugs sotalol, propranolol and metoprolol, also known as Betapace, Inderal and Lopressor. These drugs can be used to treat high blood pressure and other conditions. People taking beta blockers should avoid foods with caffeine, over-the-counter cough and cold medicines, antacids with aluminum, and antihistamines. Alcohol should also be avoided, since it can reduce the effects of beta blockers.