Rifabutin
MYCOBUTIN
What it isRNA-polymerase-inhibiting rifamycin; mycobacterial prophylaxis and treatment in people with HIV.
Why this oneMuch weaker enzyme induction than rifampin permits combinations with some antiretrovirals that rifampin disrupts.
What limits itUveitis and neutropenia require attention; interactions remain bidirectional, and body fluids turn orange.
FDA-approved for
- MAC prophylaxis (1992)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Disseminated MAC prophylaxis (advanced HIV) | adult | 300 mg QD | 300 mg QD | 300 mg QD |
Renal Mild-moderate: no adjustment; CrCl <30: consider 50% dose reduction if toxicity suspected
Hepatic Mild: no adjustment; moderate-severe: not studied
Instructions
- For GI upset, may give 150 mg BID with food
- May be mixed with food such as applesauce
- Dose reduction may be needed with certain concomitant drugs
Contraindications
- Coadministration with cabotegravir/rilpivirine extended-release injectable suspension
Cautions
- Uveitis (dose-related; higher risk at >300 mg or with clarithromycin/fluconazole) — interrupt and refer for ophthalmologic evaluation
- Neutropenia/leukopenia, thrombocytopenia
- Severe cutaneous adverse reactions (DRESS, SJS, TEN, AGEP)
- Rifamycin hypersensitivity reactions
- C. difficile-associated diarrhea
- Red-orange discoloration of urine and body fluids
Adverse reactions
- Discolored urine
- Rash
- Leukopenia/neutropenia
- Nausea
- Taste perversion
- Uveitis (higher doses/combinations)
Pregnancy Use only if potential benefit justifies risk; animal fetal effects (decreased viability, skeletal variants)
Lactation Undefined
NO BOXED WARNINGS
Principal riskUveitis and neutropenia
Cost, est. cash$10–$300/month
Generic entry2014
Classes and tags
Clinical profile
Legacy pregnancy categoryUnknown / historical label unavailable
Defining liabilityGenerally tolerated at therapeutic doses; clinically important risks are agent-specific and increase with interactions or organ impairment.
Mechanism of action: Rifabutin ballicule
