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 down 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 in order 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.
It lasts 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 32 common medications that may interact with grapefruit, categorized by use.
Some cholesterol medications
Some cholesterol medications called statins are affected by grapefruit.
Statins work by limiting the natural production of cholesterol. This improves the profile of lipoproteins in the blood and decreases deaths from heart disease in patients at risk of it.
Statins can cause rhabdomyolysis, or the breakdown of muscle tissue. This leads to muscle weakness, pain and occasionally kidney damage.
Grapefruit increases the blood levels of three common statins substantially, increasing the risk of rhabdomyolysis:
One study showed that drinking a glass of grapefruit juice with simvastatin or lovastatin increased blood levels of these statins by 260%.
Summary: Grapefruit can increase the side effects of some statin cholesterol medications, causing muscle damage.