Critical
Clarithromycin × Sirolimus
Macrolide antibiotic×Selective immunosuppressant, mTOR inhibitor
Mechanism
Clarithromycin inhibits CYP3A4 (main sirolimus pathway) and P-gp. Sirolimus rises 8-fold – severe immunosuppression, nephrotoxicity, thrombotic microangiopathy.
Symptoms
Rising creatinine, thrombocytopenia, hepatitis within 5-7 days.
Management
Combination contraindicated. Alternative – azithromycin (no CYP3A4 inhibition) or other antibiotic class.
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.
Sources
- FDA: Biaxin (clarithromycin) prescribing information – CYP3A4 inhibition (2018)– FDA Biaxin label, Drug Interactions §7
- FDA: Rapamune (sirolimus) prescribing information – strong CYP3A4 inhibitor contraindications (2020)– FDA Rapamune label, Drug Interactions §7.2
- FDA: Rapamune (sirolimus) prescribing information (2017)