In “Statins and elevated liver tests: What’s the fuss?”1 in the July issue, you emphasize—in a Fast Track—that cyclosporins and macrolide antibiotics are relatively contradicted in statin use. My concern is that physicians with patients taking a cyclosporin or a macrolide antibiotic will completely avoid statin use, even in patients at high risk for coronary artery disease. That’s not necessary, however. There are significant differences in the pharmacokinetics of various statins, and some of them can be used safely with these drugs.
Allow me to clarify:
- Macrolide antibiotics are metabolized through the cytochrome P450-3A4 pathway only. Therefore, only statins with significant 3A4 pathway involvement (atorvastatin, lovastatin, and simvastatin) are contraindicated in patients taking macrolides.
- Although all statins interact with cyclosporin, this interaction is a matter of degree: The 3 statins cited above interfere with cyclosporin through the cytochrome P450-3A4 pathway; rosuvastatin and pravastatin interfere via the hepatic organic ion transporter system and the P-glycoprotein efflux pump. The safest statin for posttransplant patients and others on long-term cyclosporin therapy is fluvastatin.2
- Pravastatin has no significant cytochrome P450 drug interactions. It is therefore the preferred statin for patients with HIV, who often require lifelong multiple drug combinations, many of which have cytochrome P450-3A4 drug interactions.
It is important for physicians to be aware of such differences and to realize that there are statins that patients can take when they are taking macrolides, cyclosporins, or azole antifungals and have high cardiovascular risks.
Frank J. Johnson, Jr, MD, FAAFP
Diplomate, American Board of Clinical Lipidology
Bluefield Family Medicine, Bluefield, VA