From the Guidelines
The recommended dose of rifabutin for Mycobacterium avium-intracellulare (MAI) infection is 300 mg once daily. This medication is typically used as part of a multidrug regimen that includes other antimycobacterial agents such as clarithromycin and ethambutol. For MAI prophylaxis in immunocompromised patients, a lower dose of rifabutin at 300 mg daily can be used as monotherapy.
Key Considerations
- Dose adjustments are necessary in patients with renal impairment or when taking certain medications that interact with rifabutin, particularly protease inhibitors or non-nucleoside reverse transcriptase inhibitors, where the dose may need to be reduced to 150 mg daily or increased to 450-600 mg daily depending on the specific interaction 1.
- Rifabutin works by inhibiting bacterial DNA-dependent RNA polymerase, preventing bacterial replication.
- Common side effects include reddish-orange discoloration of body fluids, neutropenia, uveitis, and gastrointestinal disturbances.
- Regular monitoring of complete blood counts and liver function tests is recommended during treatment.
Evidence-Based Recommendations
- The most recent and highest quality study recommends a dose of 300 mg once daily for MAI infection 1.
- Other studies support the use of rifabutin as part of a multidrug regimen for MAI treatment and prophylaxis 1.
Clinical Implications
- Clinicians should carefully weigh the potential benefits of MAI prophylaxis against the potential for toxic effects and drug interactions.
- Patients receiving rifabutin should be monitored for toxicity, including visual acuity, liver enzymes, and complete blood counts.
- Dose adjustments should be made based on individual patient needs and response to treatment.
From the FDA Drug Label
DOSAGE AND ADMINISTRATION It is recommended that rifabutin capsules USP be administered at a dose of 300 mg once daily. The dose of rifabutin for MAI is 300 mg once daily 2.
- The dose may be adjusted to 150 mg twice daily for patients with gastrointestinal upset.
- A dose reduction of 50% may be necessary for patients with severe renal impairment.
From the Research
Dose of Rifabutin for MAI
- The recommended dose of rifabutin for the treatment of Mycobacterium avium complex (MAC) lung disease is 300 mg/d in multidrug regimens that include a macrolide 3.
- A study comparing two regimens for the treatment of MAC bacteremia in AIDS patients found that rifabutin at a dose of 600 mg daily was effective, but the dose was reduced by half after 125 patients were randomized due to adverse events, including uveitis 4.
- Another study found that once-weekly azithromycin was more effective than daily rifabutin for the prevention of disseminated MAC infection, and that the combination of rifabutin and azithromycin was even more effective, but less well tolerated 5.
- A review of rifabutin for the prevention of disseminated MAC infection in AIDS patients found that the drug was effective at a dose of 300 mg daily, but that adverse effects occurred in 16% of patients 6.
- A risk-benefit assessment of therapies for MAC infections found that rifabutin was associated with adverse effects, including gastrointestinal symptoms and liver enzyme elevations, and that the drug interacted with other medications, including macrolides and HIV protease inhibitors 7.