Clarithromycin and Lorlatinib interaction
Clarithromycin and Lorlatinib: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Lorlatinib (Lorbrena) label · effective 2026-06-26
• Strong CYP3A Inhibitors : Avoid concomitant use; reduce LORBRENA dose if concomitant use cannot be avoided.
Strong CYP3A Inhibitors Avoid concomitant use of LORBRENA with a strong CYP3A inhibitor.
Concomitant use with a strong CYP3A inhibitor increased lorlatinib plasma concentrations [see Clinical Pharmacology (12.3) ] , which may increase the incidence and severity of adverse reactions of LORBRENA.
From the Clarithromycin label · effective 2026-01-01
Miscellaneous Cytochrome P450 Inducers: Efavirenz Nevirapine Rifampicin Rifabutin Rifapentine Use With Caution Inducers of CYP3A enzymes, such as efavirenz, nevirapine, rifampicin, rifabutin, and rifapentine will increase the metabolism of clarithromycin, thus decreasing plasma concentrations of clarithromycin, while increasing those of 14-OH-clarithromycin.
Alternative antibacterial treatment should be considered when treating patients receiving inducers of CYP3A.
Since the microbiological activities of clarithromycin and 14-OH-clarithromycin are different for different bacteria, the intended therapeutic effect could be impaired during concomitant administration of clarithromycin and enzyme inducers.
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.