Atorvastatin × Azithromycin

Atorvastatin is broken down by the CYP3A4 enzyme and carried by the transporter P-glycoprotein (atorvastatin SmPC). Azithromycin is a weak inhibitor of cytochrome P450 enzymes, but inhibition of CYP3A4 cannot be fully ruled out (azithromycin SmPC). In a study, azithromycin 500 mg daily for 3 days did not change blood levels of atorvastatin 10 mg (azithromycin labels). Even so, post-marketing cases of rhabdomyolysis have been reported in patients taking azithromycin with statins (azithromycin SmPC).

Muscle pain, weakness, cramps or tenderness, sometimes with malaise and fever. In rhabdomyolysis, urine turns dark from myoglobin and there is a risk of acute kidney injury (statin SmPCs).

Use the combination with caution: post-marketing cases of rhabdomyolysis have been reported in patients taking azithromycin with statins (azithromycin SmPC). The atorvastatin label of the US Food and Drug Administration (FDA) advises weighing the risks and benefits of combining atorvastatin with macrolides and watching for signs of muscle damage, especially when starting treatment and when raising the dose of either drug. Ask the patient to report muscle pain, cramps or weakness at once, especially with fever or malaise. If these occur, measure creatine kinase (CK): stop atorvastatin if CK is above 5 times the upper limit of normal (atorvastatin SmPC).