Grapefruit can alter the effects of medications

This citrus is considered part of a healthy diet, but combining it with some medications can lead to undesirable effects. Substances in grapefruit affect the breakdown of drugs in the body, which either enhances their effects or makes them less effective.

For this reason, the U.S. Food and Drug Administration (FDA) requires that warnings about incompatibility with grapefruit juice appear on the packaging of certain medications. This applies to prescription drugs as well as those sold over-the-counter.

The list of medications that can be affected by this fruit is quite extensive. Among them:

• Statins (cholesterol-lowering agents);
• Medications for hypertension;
• Corticosteroids used for Crohn’s disease;
• Medications for heart rhythm disorders (amiodarone);
• Antihistamines.

However, not all drugs from these categories react with grapefruit juice. The intensity of the interaction depends on the specific drug, the characteristics of the body and the amount of juice drunk.

In most cases, grapefruit increases the concentration of the drug in the blood by blocking the enzyme CYP3A4, which is responsible for its breakdown in the intestine. As a result, the drug stays in the body longer, which can increase side effects. For example, if you combine grapefruit juice with statins, it increases the risk of liver and muscle tissue damage.

But the opposite can also happen: for some drugs, such as fexofenadine (for seasonal allergies), grapefruit reduces absorption, making the drug less effective. This is due to the fact that the juice interferes with the work of special transporter proteins that help substances to penetrate into the cells.

In order not to face undesirable consequences, it is important to check in advance whether it is safe to combine your drug with grapefruit:

• Consult your doctor or pharmacist;
• Pay attention to the packaging of over-the-counter medications: if there is a note about incompatibility with fruit juices, it is better to exclude them from your diet;
• Check the composition of juices and drinks, as they may contain grapefruit concentrate.

In addition to grapefruit, pomelo, tangelo and Seville oranges, from which marmalade is made, may have a similar effect. If your drug is incompatible with grapefruit juice, it is better to refuse these fruits as well.

Grapefruit’s effect on medications is an important but often underestimated factor. Before including this citrus in your diet, it is worth making sure that it will not harm your health.