rifabutin


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rifabutin

 [rif″ah-bu´tin]
an antibacterial used for the prevention of disseminated Mycobacterium aviumcomplex disease in patients with advanced HIV infection; administered orally.

rifabutin

Mycobutin

Pharmacologic class: Rifamycin derivative

Therapeutic class: Antimycobacterial

Pregnancy risk category B

Action

Inhibits RNA synthesis by blocking RNA transcription in susceptible organisms (mycobacteria and some gram-positive and gram-negative bacteria)

Availability

Capsules: 150 mg

Indications and dosages

To prevent disseminated Mycobacterium avium intracellulare complex in patients with advanced human immunodeficiency virus (HIV) infection

Adults: 300 mg P.O. daily as a single dose or in two divided doses

Off-label uses

• Tuberculosis

• Prophylaxis and treatment of M. avium intracellulare in children

Contraindications

• Hypersensitivity to drug

• Active tuberculosis

Precautions

Use cautiously in:

• severe hepatic disease

• pregnant or breastfeeding patients.

Administration

• Give in divided doses twice daily with food to reduce GI upset.

Adverse reactions

CNS: headache, asthenia, weakness

CV: pressure sensation in chest

EENT: uveitis; discolored tears, saliva, or sputum

GI: nausea, vomiting, diarrhea, dyspepsia, abdominal pain, eructation, flatulence, discolored feces, anorexia

GU: discolored urine

Hematologic: eosinophilia, neutropenia, leukopenia, thrombocytopenia Musculoskeletal: joint pain, myalgia

Respiratory: dyspnea

Skin: rash, discolored skin or sweat

Other: abnormal taste, fever, flulike symptoms

Interactions

Drug-drug. Clarithromycin, itraconazole, saquinavir: reduced blood levels and efficacy of these drugs

Delavirdine: decreased delavirdine blood level, increased rifabutin blood level

Drugs metabolized by liver (such as zidovudine): altered blood levels of these drugs

Hormonal contraceptives: decreased contraceptive efficacy

Indinavir, nelfinavir, ritonavir: increased rifabutin blood level

Drug-diagnostic tests. Alanine aminotransferase, aspartate aminotransferase, eosinophils: increased levels

Neutrophils, platelets, white blood cells: decreased counts

Drug-food. High-fat foods: delayed drug absorption

Patient monitoring

• Monitor CBC with white cell differential. Watch for signs and symptoms of blood dyscrasias.

• Assess nutritional status.

• Closely monitor vital signs and temperature. Stay alert for dyspnea and flulike symptoms.

Patient teaching

• Advise patient to take twice daily with food (but not high-fat food) if GI upset occurs. To further minimize GI upset, teach him to eat small, frequent servings of healthy food and drink plenty of fluids.

• Instruct patient to take exactly as prescribed, even after symptoms subside.

Tell patient to immediately report easy bruising or bleeding.

• Tell patient drug may turn tears, urine, and other body fluids reddish or brownish orange. Instruct him not to wear contact lenses during therapy because drug may stain them permanently.

• Inform patient that drug occasionally causes eye inflammation. Instruct him to report symptoms promptly.

• Caution patient to avoid driving and other hazardous activities until effects of drug are known.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and foods mentioned above.

rifabutin

Mycobutin® AIDS A semisynthetic rifamycin used to prevent MAC in AIDS Pts with < 75 T4 cell/mm3, or combined with other drugs to treat MAC; it ↓ anemia, fatigue, fever, hospitalization, Karnovsky performance score, prevents ↑ alk phos seen in advanced AIDS Side effects Kidney and liver damage, BM suppression, rash, fever, GI stress. See AIDS, Mycobacterium avium-intercellulare complex.

rifabutin

A drug used to treat tuberculosis of the lungs and to prevent the development of lung TB in AIDS patients. A brand name is Mycobutin.
References in periodicals archive ?
Antibiotic MIC Susceptibility Streptomycin >32 R Isoniazid <0.03 S Rifampin <0.12 S Ethambutol 1 S Rifabutin <0.12 S Ethionamide <0.3 S Amikacin 0.25 S Moxifloxacin 0.25 S para-Aminosalicylic acid <0.5 S Cycloserine 8 S Capreomycin 1.2 S Levofloxacin 0.5 S MIC indicated minimum inhibitory concentration (ug/mL).
The new guidelines provide additional recommendations regarding use of rifampin with antiretroviral therapy; these recommendations are critical in regions where rifabutin is unavailable.
1995,288:201-207 (37) TABLE 3 Drugs that induce or inhibit CYP3A4 Inducers Barbiturates Glucocorticoids Carbamazepine Modafinil Dexamethasone Nevirapine Efavirenz Phenobarbital Weak/moderate Amiodarone Diltiazem inhibitors Anastrozole Fluconazole Chloramphenicol Fluoxetine Cimetidine Fluvoxamine Ciprofloxacin Metronidazole Clotrimazole Mibefradil Danazol Miconazole Delavirdine Strong inhibitors * Clarithromycin Indinavir Erythromycin Itraconazole Inducers Phenylbutazone Rifabutin Phenytoin Rifampin Pioglitazone St.
A partial list of these medications includes ciprofloxacin, erythropoietin, lamivudine (for the treatment of hepatitis B), fluconazole, ketoconazole, itraconazole, ganciclovir (to treat CMV), ribavirin and interferon (to treat hepatitis C), rifabutin (to treat MAI), and famciclovir (to treat Herpes Simplex).
Similarly, twice-weekly rifampin or rifabutin should not be used in patients whose CD4 counts are below 100 cells/[micro]L.
HIV-infected adults should be dosed the same as those without HIV, but rifampin or rifabutin should be used instead of rifapentine because of high rates of relapse among HIV patients given rifapentine, the recommendations state.
The FDA has appfoved rifabutin, a drug to prevent Mycobacterium avium complex (MAC) in patients who have advanced HIV infection.
Although none of the Queensland cohort underwent drug susceptibility testing, review of previous cases suggests that a combination of rifabutin, ethambutol, and clarithromycin may be an effective drug regimen, with moxifloxacin/levofloxacin, sulfamethoxazole, pyrazinamide, and linezolid as other potential agents (3-7).
interjectum susceptibilities were reported (Table 1), the therapy was modified to oral ciprofloxacin 500 mg twice a day, azithromycin 250 mg daily, and rifabutin 300 mg daily for additional 9 months.
For third-line therapy, there are no current recommendations except targeted drugs that should be checked for susceptibility before the start of treatment like tetracyclines, rifabutin and furazolidone.
Culprits include zidovudine (AZT) and stavudine (d4T), co-trimoxazole (Bactrim) and the antituberculosis drugs isoniazid, rifampicin and rifabutin. (4) In patients presenting with anaemia, baseline haematinic studies including serum ferritin, serum [B.sub.12] and red-cell folate are essential, and significant deficiencies should routinely be excluded.
His current medications included azithromycin, ethambutol, rifabutin and trimethoprim-sulfamethoxazole.