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. Metoprolol is a beta blocker