A common breakfast food in the United States, many enjoy the tangy and sweet taste of the citrus fruit grapefruit, either fresh or as juice. Those taking certain medications, however, may need to be careful. Constituents of grapefruit can interact with certain pharmaceuticals, including statin drugs, which are used for lowering cholesterol, producing adverse reactions.
Statin Drugs
Statins are a class of drug that effectively lower cholesterol by preventing the production of a substance required to make cholesterol in the body. They may also help in the process of reabsorbing cholesterol, which can help to reduce plaque buildup within the cardiovascular system. Statins include drugs such as Lipitor, Zocor, Crestor and Pravachol, among others. Your doctor may prescribe a statin drug if your total cholesterol is above 240 or your LDL cholesterol is 130 or higher.
Statin Transport
When ingested, grapefruit can interfere with a type of carrier molecule, known as P-glycoprotein. This molecule, produced in the intestinal wall, is part of the internal transport system that would normally carry statin drugs to the intestines for metabolism and disposal. Grapefruit can significantly inhibit this molecule, allowing statin drugs to build up in the body.
Statin Metabolism
Normally, statin drugs are metabolized by the body and excreted after a certain amount of time. This controls their overall effect. However, a compound found only in grapefruit, called naringenin, deactivates a specific enzyme within the small intestine, called cytochrome P450 3A4, that is essential for the metabolism of statin drugs. Without this enzyme, statins can concentrate and significantly increase within the body, amplifying their effect.
Risks
Excessive amounts of statins in the body can cause an increase in liver enzymes. If left untreated, this can produce permanent liver damage. Statins can also produce muscle pain and tenderness, known as statin myopathy. In some cases, muscle cells can even break down in a process known as rhabdomyolysis. This, in turn, can release a protein called myoglobin in the bloodstream, which can cause kidney damage.
Resolution
If you are currently on a statin drug, the likelihood is that you will need to continue taking the medication throughout your life to maintain proper cholesterol levels. Since this medication will take priority, it is best to avoid the consumption of grapefruit, in any form, to prevent possible adverse drug interactions.
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