Simvastatin and Grapefruit

It is not advised to combine simvastatin and grapefruit or grapefruit-containing products because they may significantly increase the levels of simvastatin in the blood. One glass of grapefruit juice taken with a 40mg simvastatin tablet may raise the concentration of the medication in the blood 4-fold. The effect is approximately the same a taking 160mg instead of 40mg of simvastatin. High levels of the medication in the blood increase the risk of developing some of side effects of simvastatin, such as muscle pain, or even the most severe, life-threatening side effects, such as serious muscle damage (rhabdomyolysis or myopathy) or kidney failure.simvastatin and grapefruit

How Does Simvastatin Interact with Grapefruit?

Simvastatin is metabolized in the body through an enzyme system called the cytochrome P450 system. It is supposed that grapefruit products slow down breakdown of simvastatin by interfering with this the enzyme system which is essential for the process. Scientifically, this is called inhibition of CYP3A4-mediated first-pass metabolism. However, clinical studies taken at the Department of Clinical Pharmacology, University of Helsinki, and Helsinki University Central Hospital, Finland by Kivistö KT, Lilja JJ and Neuvonen PJ showed that grapefruit products may increase simvastatin concentration in the blood 10-fold or even more. However, the exact mechanism of the effect of grapefruit on simvastatin is metabolizing is still being studied.

What if I Drank Much grapefruit Juice While on Simvastatin?

Tell your doctor about that immediately! Generally, researchers suggest decreasing the dose of simvastatin if large amount of grapefruit juice of other grapefruit products were consumed, assuming that the damage to the body from the high concentrations of simvastatin outweighs its therapeutic action on high cholesterol levels. Remember that you should avoid taking simvastatin tablets and grapefruit together.