Rifabutin

Oral
Pulmonary tuberculosis

Oral
Nontuberculous mycobacterial infections

Oral
Prophylaxis of Mycobacterium avium complex infections in immunocompromised patients

CrCl	Dosage
<30	Reduce dose by 50%.

Hypersensitivity to rifabutin and other rifamycins.

Renal and hepatic impairment. Pregnancy and lactation.

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).

May impart a red-orange colour to the urine, skin and body secretions. Contact lenses, esp soft, may be permanently stained.

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.

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 may delay absorption.

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.

Source: National Center for Biotechnology Information. PubChem Database. Rifabutin, CID=135398743, https://pubchem.ncbi.nlm.nih.gov/compound/Rifabutin (accessed on Jan. 22, 2020)

Store at 25°C.

Anti-TB Agents

Anon. Rifabutin. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 18/08/2014.

Buckingham R (ed). Rifabutin. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 18/08/2014.

Rifabutin Capsule (Greenstone LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 18/08/2014.