ModerateHMG-CoA reductase inhibitors (statins)×Imidazole derivatives (antiprotozoal / antibacterial)
Updated · Methodology
Mechanism
Metronidazole does not block CYP3A4 but increases myopathy risk with statins (mechanism not fully established; reported in post-marketing data). The effect is rare.
Symptoms
Pain and weakness in large muscle groups (thighs, shoulders, calves), dark urine, elevated creatine kinase. Symptoms usually appear 2–6 weeks after starting the combination.
Management
For short metronidazole courses (5–7 days), no special adjustment. In patients with myopathy risk factors, check creatine kinase on muscle symptoms. For prolonged metronidazole therapy, temporarily reduce atorvastatin.
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.
Summary of a multi-drug list →
Medicine list: everything you take in one place →
Sources
- FDA: Lipitor (atorvastatin) prescribing information (2017)– ; DailyMed setid a60cc18b-0631-4cf0-b021-9f52224ece65