Grapefruit Warning: It Can Interact with Common Medications

Grapefruit is a delicious citrus fruit with many health benefits. However, it can interact with some common medications, altering their effects on your body.

Here’s a closer look at common drugs that may have dangerous interactions with grapefruit.

Talk to your physician before changing your use of any medication.

How does it interact with medications?

Medications are processed in your liver and small intestine by a specialized group of proteins called cytochrome P450 (CYPS).

CYPS break down medications, reducing the blood levels of many of them.

Grapefruit and a few of its close relatives, such as Seville oranges, tangelos, pomelos, and Minneolas, contain a class of chemicals called furanocoumarins.

Furanocoumarins disrupt the normal function of CYPS. In fact, studies show that they increase the blood levels of over 85 medications.

By slowing the way in which CYPS normally break down medications in your gut and liver, grapefruit can increase the side effects of these drugs.

There are three things to know to understand if and how you can safely consume grapefruit with these medications.

It doesn’t take much. One whole grapefruit or one glass of grapefruit juice is enough to alter how these medications affect you.

Its effects last several days. Grapefruit’s ability to affect medication lasts for 1–3 days. Taking your medication a few hours apart from consuming it isn’t long enough.

It’s significant. For a small number of drugs, grapefruit’s effects can be serious.

With that in mind, here is detailed information about common medications that may interact with grapefruit, categorized by use.

Certain blood pressure medications

Most types of blood pressure medicines are not affected by grapefruit.

However, the following four blood pressure medications should be used cautiously:

- Felodipine

- Nifedipine (Procardia) - Losartan (Cozaar) - Eplerenone (Inspra) The first two medications in this list are known as calcium channel blockers. They work by changing the way your blood vessels use calcium, relaxing the vessels, and relieving blood pressure.

The last two medications in this list work by decreasing the activity of a hormone called angiotensin 2, which naturally increases blood pressure.

One study found blood levels of nifedipine increased dramatically when taken with about 2 cups (500 ml) of grapefruit juice, compared with no juice. This resulted in a rapid drop in blood pressure, which could be dangerous if unsupervised.

Losartan is unusual in that grapefruit decreases its effects, potentially limiting its ability to control blood pressure.

Eplerenone works similarly to losartan, but its levels increase when taken with grapefruit. Excessive eplerenone levels can cause too much potassium in the blood, which can interfere with heart rhythm.