rifabutin (Mycobutin)
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Introduction
Tradename: Mycobutin.
Indications
- prevention of disseminated Mycobacterium avium complex (MAC) in patients with advanced HIV infection
- treatment of tuberculosis in combination with other agents
Contraindications
- leukopenia (WBC < 1000/mm3)
- thrombocytopenia (platelets < 50,000/mm3)
Dosage
- 300 mg PO QD, or 150 mg PO BID
- 150 mg PO QD if concurrent use of protease inhibitor (indinavir or nelfinavir are protease inhibitors of choice)
Capsule: 150 mg.
Pharmacokinetics
- distributes to body tissues including lungs, liver, spleen, eyes & kidneys
- protein binding 85%
- metabolized in the liver by cyt P450 3A4 to active & inactive metabolites
- terminal elimination 1/2life: 16-69 hours
- renal & biliary clearance of unchanged drug is 10%
- 30% excreted in the feces
elimination via liver
protein binding = 85 %
1/2life = 16-69 hours
Adverse effects
- common (> 10%)
- less common (1-10%)
- uncommon (< 1%)
- other
Drug interactions
- clarithromycin, fluconazole & antiretroviral protease inhibitors increase serum levels of rifabutin[3]
- dosage adjustment may be required[3]
- indinavir or nelfinavir are protease inhibitors of choice with rifabutin
- rifabutin increases levels of
- rifabutin may decrease ketoconazole levels
- any drug that inhibits cyt P450 3A4 may increase levels of rifabutin
- any drug that induces cyt P450 3A4 may diminish levels of rifabutin
- rifabutin induces cyt P450 3A4, thus induces its own metabolism & metabolism of other cyt P450 3A4 substrates
- drug interaction(s) anticonvulsants with anti-bacterial agents
- drug interaction(s) of antibiotics with warfarin
Laboratory
More general terms
Additional terms
Component of
References
- ↑ The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
- ↑ Kaiser Permanente Northern California Regional Drug Formulary, 1998
- ↑ Jump up to: 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Medical Knowledge Self Assessment Program (MKSAP) 11, 17. American College of Physicians, Philadelphia 1998, 2015