Rifampin and Ritonavir interaction
Rifampin and Ritonavir: 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 Rifampin (Rifadin IV) label · effective 2026-05-27
(See WARNINGS .) Rifampin is contraindicated in patients who are also receiving ritonavir-boosted saquinavir due to an increased risk of severe hepatocellular toxicity.
…Concentrations Administered with rifampin 600 mg daily, unless otherwise specified Drug or Drug Class and Prevention or Management Clinical Effect AUC = area under the time-concentration curve Antiretrovirals Prevention or Management: Concomitant use is contraindicated (see CONTRAINDICATIONS ) Atazanavir Decrease AUC by 72% Darunavir Rifampin dosage used concomitantly with…
Cabotegravir Decrease AUC by 59% Fostemsavir Decrease AUC by 82% Lenacapavir (SUNLENCA ® ) Indicated for the treatment of human immunodeficiency virus-1 (HIV-1) infection Decrease AUC by 84% Antiretrovirals Prevention or Management: Avoid concomitant use Zidovudine Decrease AUC by 47% Indinavir Decrease AUC by 92% Efavirenz Decrease AUC by 26% Antiretrovirals Prevention…
Drug Interactions Pharmacodynamic Interactions Healthy subjects who received rifampin 600 mg once daily concomitantly with saquinavir 1000 mg/ritonavir 100 mg twice daily (ritonavir-boosted saquinavir) developed severe hepatocellular toxicity.
From the Ritonavir (Norvir) label · effective 2026-07-23
Saquinavir/ritonavir in combination with rifampin is not recommended due to the risk of severe hepatotoxicity (presenting as increased hepatic transaminases) if the three drugs are given together.
Antimycobacterial: rifampin ↓ ritonavir May lead to loss of virologic response.
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.