Why Zocor cannot be taken with grapefruit or its juice?

Question

I heard that simvastatin (Zocor) cannot be taken with grapefruit juice? Is that so, and why?

Answer 1

Whole grapefruit as well as grapefruit juice contains sunstances (furanocoumarins) that slow down metabolism of statins by inhibiting the enzyme called intestinal cytochrome P450 3A4.

This may result in abnormally high blood level of the drug leading to potentially serious side effects and toxicity. Therefore, people taking statins should avoid both grapefruit and any grapefruit-containing products.

Answer 2

Actually, it is okay to drink grapefruit juice with Crestor, a statin whose generic name is rosuvastatin, not simvastatin. Crestor, unlike most of the other statins, is not metabolized by the CYP3A4 enzyme. It is therefore unaffected by grapefruit or grapefruit juice.

Zocor (simvastatin), however, is one of the statins metabolized by the CYP3A4 enzyme. This does not mean that people taking simvastatin have to avoid grapefruit juice altogether--it just means they need to moderate how much they drink. According to the most recent recommendations from the FDA, there should not be a significant interaction between simvastatin and grapefruit juice as long as the quantity of grapefruit juice consumed is less than one quart a day.