Rifabutin


Concise Prescribing Info
Indications/Uses
Listed in Dosage.
Dosage/Direction for Use
Adult : PO Prophylaxis of M. avium complex infections in immunocompromised patients 300 mg once daily. Nontuberculous mycobacterial infections 450-600 mg/day in combination regimens for up to 6 mth after negative cultures are obtained. Pulmonary TB 150-450 mg/day in combination regimens for at least 6 mth.
Dosage Details
Oral
Pulmonary tuberculosis
Adult: 150-450 mg daily, as part of multidrug regimen, given for at least 6 mth.

Oral
Nontuberculous mycobacterial infections
Adult: 450-600 mg daily, as part of a multidrug regimen, given for up to 6 mth after negative cultures are obtained. May reduce dose to 300 mg when given w/ clarithromycin (or other macrolides) and/or fluconazole (or related compounds).

Oral
Prophylaxis of Mycobacterium avium complex infections in immunocompromised patients
Adult: 300 mg once daily.
Renal Impairment
CrCl Dosage
<30 Reduce dose by 50%.
Contraindications
Hypersensitivity to rifabutin and other rifamycins.
Special Precautions
Renal and hepatic impairment. Pregnancy and lactation.
Adverse Reactions
Rash, GI disturbances, neutropenia, syndrome of polyarthralgia-arthritis at doses >1 g/day, uveitis esp in patients receiving clarithromycin or other macrolides, asymptomatic corneal opacities after long-term use, orange-tan skin pigmentation, flu-like syndrome, hepatitis, leucopenia, epigastric pain, erythema, ageusia.
Potentially Fatal: Clostridium difficile-associated diarrhoea (CDAD).
Patient Counseling Information
May impart a red-orange colour to the urine, skin and body secretions. Contact lenses, esp soft, may be permanently stained.
MonitoringParameters
Monitor CBC w/ differential, platelet counts, and liver enzymes periodically during treatment. Before starting prophylaxis, assess patients to ensure that they do not have active disease caused by pulmonary TB or other mycobacteria.
Drug Interactions
Increased plasma levels w/ clarithromycin (and possibly other macrolides), triazole atifungals (e.g. fluconazole, itraconazole), antivirals (e.g. indinavir, fosamprenavir, ritonavir). May reduce the activity of analgesics, anticoagulants, corticosteroids, ciclosporin, digitalis (although not digoxin), oral hypoglycaemics, narcotics, phenytoin and quinidine. Delayed GI absorption w/ p-aminosalicylic acid. May reduce serum concentration of OC or tacrolimus.
Food Interaction
Food may delay absorption.
Action
Description: Rifabutin inhibits DNA-dependent RNA polymerase in susceptible strains of Escherichia coli and Bacillus subtilis.
Pharmacokinetics:
Absorption: Readily but incompletely absorbed from the GI tract. Food may delay absorption. Time to peak plasma concentration: 2-4 hr.
Distribution: Widely distributed in body tissues and fluids. Volume of distribution: 9.32 L/kg. Plasma protein binding: Approx 70%.
Metabolism: Undergoes rapid hepatic metabolism by CYP3A4 isoenzyme to active 25-O-deacetyl and 31-hydroxy metabolites.
Excretion: Via urine (approx 53%, mainly as metabolites) and faeces (approx 30%). Mean half-life: Approx 40 hr.
Chemical Structure

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Storage
Store at 25°C.
MIMS Class
Disclaimer: This information is independently developed by MIMS based on Rifabutin from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 MIMS. All rights reserved. Powered by MIMS.com
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