Simvastatin and Grapefruit
People are typically advised to avoid combining simvastatin and grapefruit products (such as grapefruit or grapefruit juice). Clinical studies have shown that grapefruit juice can significantly increase the levels of simvastatin in the blood. This potentially dangerous combination could increase the risk of serious muscle problems that can cause the kidneys to stop working.
Is It Safe to Combine Grapefruit Products and Simvastatin?
Like several other cholesterol-lowering statins, simvastatin (Zocor®) can potentially interact with grapefruit products, such as grapefruit, grapefruit juice, and grapefruit supplements.
The Simvastatin-Grapefruit Juice Interaction
It is thought that grapefruit products, including grapefruit juice, interfere with an enzyme that is used by the body to break down simvastatin. This means that when taken with grapefruit products, simvastatin stays in the body longer. In fact, clinical studies have shown that grapefruit juice can significantly increase the levels of simvastatin in the blood. In one clinical study, levels in the blood increased by 12-fold when the drug was taken at the same time as large quantities of grapefruit juice. Even one glass of grapefruit juice daily can significantly increase the levels of simvastatin in the blood.
People taking simvastatin should not drink grapefruit juice, eat grapefruit, or use grapefruit supplements, as they can increase the levels of this medication in the blood. This, in turn, can increase the chances of developing a serious muscle problem (for example, myopathy or rhabdomyolysis) that can cause the kidneys to stop working and lead to other life-threatening complications. In rare cases, this could result in loss of life.
(Click Simvastatin and Muscle Pain for more information.)