Drug interactions with statins

There are some significant drug interactions with statins that may affect choice of statin or limit the maximum dosage that can be prescribed. Many, but not all, of the interactions are due to inhibition of the cytochrome P450 3A4 pathway. Simvastatin is the most affected in the class, but atorvastatin is often also affected. These include macrolide antibiotics, antifungal agents, medicines for HIV, calcium channel blockers, amiodarone, warfarin and ciclosporin.

This is not an exhaustive list and up-to-date information should be consulted, as well as consideration of potential interactions with herbal and over-the-counter medicines. Grapefruit/grapefruit juice also inhibits statin elimination so should be avoided when taking simvastatin and limited to no more than a small glass of juice per day in patients taking atorvastatin.