Clarithromycin and Nirmatrelvir and ritonavir interaction
Clarithromycin and Nirmatrelvir and ritonavir: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Clarithromycin label · effective 2026-01-01
Ritonavir (in patients with decreased renal function) Ritonavir: Since concentrations of 14-OH clarithromycin are significantly reduced when clarithromycin is co-administered with ritonavir, alternative antibacterial therapy should be considered for indications other than infections due to Mycobacterium avium [see Pharmacokinetics ( 12.3 )] .
Saquinavir (in patients with decreased renal function) Saquinavir: When saquinavir is co-administered with ritonavir, consideration should be given to the potential effects of ritonavir on clarithromycin (refer to ritonavir above) [see Pharmacokinetics ( 12.3 )] .
Ritonavir Etravirine Ritonavir, Etravirine: (see Ritonavir and Etravirine under “Drugs That Affect Clarithromycin Tablets” in the table below) [see Pharmacokinetics ( 12.3 )] .
Clarithromycin and other macrolides are known to inhibit CYP3A and Pgp.
Clarithromycin and other macrolides are known to inhibit CYP3A.
From the Nirmatrelvir and ritonavir (Paxlovid) label · effective 2026-02-19
Anti-infective clarithromycin, erythromycin ↑ clarithromycin ↑ erythromycin Refer to the respective prescribing information for anti-infective dose adjustment.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.