MajorAntitubercular, rifamycin derivative×HIV protease inhibitor / pharmacokinetic booster
Updated · Methodology
Mechanism
Ritonavir inhibits CYP3A4. Rifabutin rises 4-fold – severe neutropenia and uveitis risk. WHO 2024 recommends reducing rifabutin to 150 mg three times weekly.
Symptoms
Neutropenia, uveitis within 2-4 weeks.
Management
Reduce rifabutin to 150 mg three times weekly. Weekly CBC for first month.
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: Mycobutin (rifabutin) prescribing information (2018)– FDA Mycobutin label
- AEMPS: Ficha técnica: Ritonavir (nº registro 81039), sección 4.3 (2025)– AEMPS, CIMA, nº registro 81039, revisión 04/2025, sección 4.3