Why Grapefruit and Statins Don't Mix

If you take a statin medication to treat high cholesterol, depending on which one you've been prescribed, your doctor or pharmacist may have emphasized that you shouldn't eat grapefruit or drink grapefruit juice while you're on the drug. While that may sound oddly specific—why not orange juice or lemonade—there's a very good reason to steer clear of this particular citrus. Grapefruit can interact with certain statins in ways that can make the medication less effective and even cause some undesirable side effects.

Clinically, statins are known as HMG-CoA reductase inhibitors, terminology that exactly describes how they work to lower cholesterol levels—by blocking an enzyme that's key to the production of cholesterol in the body called HMG Co-A reductase. Statins are the most widely prescribed cholesterol-lowering medications because, in addition to blocking cholesterol, they affect every aspect of your lipid profile (low-density lipoproteins, or LDL; high-density lipoproteins, or HDL; and triglycerides) in a favorable way.

Grapefruit contains a compound called bergamottin that interacts with a number of enzyme systems in the body, including cytochrome P-450 and P-glycoprotein. These enzyme systems are responsible for breaking down statins (and some other drugs) into chemicals the body can use more easily. If you eat grapefruit or drink grapefruit juice when you're taking a statin, the bergamottin can prevent these enzyme systems from breaking down the drug. As a result, it can accumulate in large amounts in your body.

A buildup of statins can be very dangerous, potentially causing health problems such as elevated liver enzymes or a rare condition called rhabdomyolysis in which muscle tissue breaks down, releasing muscle fibers into the blood which can harm kidneys and even lead to kidney damage.

Not all statins are incompatible with grapefruit, but the ones that are, include:

• Lipitor (atorvastatin)
• Mevacor (lovastatin)
• Zocor (simvastatin)

Other statins haven't been shown to be as problematic when combined with grapefruit. Scientists think this may be because they aren't broken down by the same enzyme systems that metabolize the drug. They include:

• Crestor (rosuvastatin)
• Pravachol (pravastatin)
• Lesco (fluvastatin)
• Livalo (pitavastatin)

Many studies have shown that it takes just one 4-ounce serving of grapefruit juice, or a single whole fresh grapefruit, to cause statins to accumulate in the body. Thus, if you take Lipitor, Mevacor, or Zocor it's best to steer clear of grapefruit altogether. If you truly love grapefruit and hate the thought of giving it up, talk to your healthcare provider about switching you to another statin or at least lowering the dose of the one you're taking. That way, you’ll be able to enjoy your grapefruit and not suffer from the adverse effects it carries. It may even be a good idea to be cautious if you're taking another statin by not consuming grapefruit for a few hours before or after taking this medication.