Class: Antituberculosis agent
- Capsules 150 mg
Inhibits DNA-dependent RNA polymerase in susceptible strains of bacteria.
Readily absorbed from GI tract (53%). C max is 375 ng/mL. T max is 3.3 h. Bioavailability is 20% (HIV-positive patients) or 85% (healthy patients). High fat meals slow the rate without influencing extent of absorption. Steady state is 9.3 L/kg.
High lipophilicity demonstrates a high propensity for distribution and intracellular uptake. Protein binding is about 85%. Vd is 9.3 L/kg.
In the liver, there are 5 metabolites identified, 25-0-desacetyl and 31-hydroxy are the most predominant.
Eliminated in the urine (53% excreted primarily as metabolites, 5% unchanged) and feces (30%; 5% unchanged). Systemic cl is 0.69 L/h/kg. Terminal t ½ is 45 h.
Special PopulationsRenal Function Impairment
CrCl is less than 30 mL/min. AUC is increased 71%. Reduction in dosage is recommended.
Indications and Usage
Prevention of disseminated Mycobacterium avium complex (MAC) disease in patients with advanced HIV infection.
Hypersensitivity to rifabutin or other rifamycins; active tuberculosis.
Dosage and AdministrationAdults
PO 300 to 450 mg once daily.Infants and Children
PO Up to 5 mg/kg/day.
Drug InteractionsAzole antifungal agents, benzodiazepines, beta blockers, buspirone, chloramphenicol, clarithromycin, clozapine, oral contraceptives, corticosteroids, cyclosporine, delavirdine, digitoxin, disopyramide, doxycycline, erythromycin, estrogens, haloperidol, hydantoins, indinavir, losartan, methadone, mexiletine, morphine, nelfinavir, ondansetron, oral anticoagulants, quinidine, quinine, ritonavir, sulfonylureas, tacrolimus, tamoxifen, theophyllines, tocainide, toremifene, tricyclic antidepressants, troleandomycin, verapamil, zolpidem
Therapeutic efficacy may be decreased because of liver enzyme-inducing properties of rifabutin.Indinavir, itraconazole, ritonavir
May elevate rifabutin plasma levels, increasing the risk of side effects.Ketoconazole
May reduce rifabutin plasma levels, decreasing the therapeutic effects.Zidovudine
May decrease plasma levels of zidovudine.
Laboratory Test Interactions
None well documented.
Asthenia; headache; insomnia.
Anorexia; diarrhea; dyspepsia; abdominal pain; eructation; flatulence; nausea; vomiting.
Anemia; eosinophilia; leukopenia; neutropenia; thrombocytopenia.
Increased alkaline phosphatase, AST, and ALT.
Myalgia; fever; discolored saliva, sputum, tears, or skin.
Category B .
Unknown. Discontinue nursing or discontinue drug.
Safety and efficacy not established. Based on the limited data available, there is no evidence that doses higher than 5 mg/kg daily are useful.
- Inform patient that body fluids (eg, urine, feces, saliva, sputum, perspiration, tears) may be brown-orange in color and that soft contact lenses may be permanently stained. Suggest use of glasses during drug therapy.
- Instruct patient to use nonhormonal methods of birth control while taking drug.
- Instruct patient to notify health care provider of rash, nausea, vomiting, anorexia, diarrhea, abdominal pain, change in color or consistency of stools, jaundice, arthralgias, myositis, chest pressure or pain with shortness of breath, seizure activity, paresthesia, aphasia, confusion, insomnia, excessive fatigue, fever, or infection.
- Instruct patient to report photophobia, excessive tearing, or eye pain immediately.
Copyright © 2009 Wolters Kluwer Health.