Grapefruit juice interacts with some calcium channel blockers and increases the level of the medicine in your blood. Grapefruit juice does not affect diltiazem. If you're taking any of the medicines below, seek advice from your pharmacist or doctor if you wish to include grapefruit or grapefruit juice in your diet. Furanocoumarins inhibit an enzyme, cytochrome P450 3A4, that is responsible for the inactivation of approximately half of all drugs. You should check with your doctor before drinking grapefruit juice.This list is not exhaustive and there are a number of other drugs that may interact with grapefruit. They're used as part of the treatment of conditions such as Grapefruit juice interacts with some calcium channel blockers and increases the level of the medicine in your blood. Some medicines used in the treatment of cancers may interact with grapefruit juice. Health care providers should be informed of which medications patients are taking, including any Warnings labels on prescription bottles should be followed. Calcium channel blockers are medicines that relax the muscles that make up the walls of your arteries. When grapefruit juice is consumed, the enzyme’s ability to break down the drug for elimination is decreased. Commonly prescribed macrolide antibiotics include erythromycin (E-Mycin, Erythrocin), azithromycin (Zithromax, Zmax) and clarithromycin (Biaxin). The main group of antibiotics that may be affected by eating grapefruit or drinking grapefruit juice are called macrolides. The authors report that grapefruit, grapefruit juice, and some other citrus fruit, including Seville oranges, limes and pomelos, contain a class of chemical called furanocoumarins. These fruits also contain furanocoumarins and may cause the same interactions as grapefruit. If your usual diet includes grapefruit or grapefruit juice and you've been prescribed a medicine that's affected by grapefruit, speak to your GP or pharmacist. Patients should avoid consuming large amounts of orange juice to prevent fluctuations in atenolol blood drug levels.This is one of the most well-known orange juice drug interactions and one of the first ones identified. Orange juice may block the absorption and lead to lower levels of atenolol in the blood. This may affect heart rhythm or function ( 1 ). We comply with the HONcode standard for trustworthy health information - Grapefruit contains compounds known as furanocoumarins that block the CYP3A4 enzymes. The FDA has required that some prescription and over-the-counter (OTC) drugs taken by mouth include warnings against drinking grapefruit juice or eating grapefruit while taking the drug, Huang says. But it's interaction is a bit different. This can increase the risk of side effects or alter the effect the medicine has. The effects of grapefruit juice on certain medications can last for over 24 hours. If you're taking any of the medicines below, seek advice from your pharmacist or doctor if you wish to include grapefruit or grapefruit juice in your diet. If an interaction is found to occur, it may be possible that an alternative medication can be prescribed and the interaction can be avoided.Examples of some of the most common grapefruit or grapefruit juice drug interactions that can occur include:There are numerous other drug interactions with grapefruit and grapefruit juice; this is not a complete list. If you're taking any of these medicines, do not drink grapefruit juice without consulting your doctor. In most cases, it increases the level of the medicine in your blood. However, orange or apple juice can cause an interaction with fexofenadine (Allegra) and aliskerin (Tekturna).You should use caution when eating anything made with the seville orange (often used in marmalades), the pomelo (a citrus fruit with a similar flavor to grapefruit but less tart), and limes. Grapefruit juice decreases the activity of the cytochrome P450 3A4 (CYP3A4) enzymes that are responsible for breaking down many drugs and toxins. Grapefruit juice increases the level of simvastatin in your blood and makes side effects more likely. Currently, healthcare professionals advise it is safe to drink grapefruit juice and eat grapefruit if you're taking other types of statins. Atenolol, a beta blocker agent also used to treat high blood pressure and angina (chest pain) may have an interaction with orange juice, but the health implications are not really known. Select one or more newsletters to continue. Atorvastatin interacts with grapefruit juice if you drink large quantities (more than 1.2 litres daily), but an occasional glass is thought to be safe. For most medications, orange juice, apple juice, or grape juice can be consumed instead of grapefruit juice without any concern for an interaction. Other juices, like apple and orange, are now also being found to interact with some medications. Grapefruit also increases levels of the HIV medications rilpivirine and maraviroc, in addition to primaquine-related antimalarial drugs. Examples of common medications that interact with grapefruit juice include certain statin cholesterol drugs such as atorvastatin (Lipitor), lovastatin, simvastatin (Zocor), felodipine (Plendil) and other calcium channel blockers, clarithromycin (Biaxin), and loratadine (Claritin). Antibiotics Affected by Grapefruit. Studies with these fruits are not as frequent, so their risk level is not fully known.Pomegranate juice (from a berry) is a delicious fruit that is full of antioxidants and vitamin C. However, this "superfood" has an interaction with the breast cancer treatment Increasingly, more drugs are being shown to interact with other juices.