Mycobutin Side Effects

Generic name: rifabutin

Note: This document contains side effect information about rifabutin. Some of the dosage forms listed on this page may not apply to the brand name Mycobutin.

Some side effects of Mycobutin may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

For the Consumer

Applies to rifabutin: oral capsule

Get emergency medical help if you have any of these signs of an allergic reaction while taking rifabutin (the active ingredient contained in Mycobutin) hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have any of these serious side effects:

• severe skin rash or itching;

• pale skin, weakness, easy bruising or bleeding;

• fever, chills, body aches, flu symptoms; or

• eye pain or redness, vision loss.

Less serious side effects of rifabutin may include:

• red, orange, or brown discoloration of your skin, tears, sweat, saliva, urine, or stools;

• nausea, vomiting, diarrhea;

• stomach pain;

• belching, bloating, loss of appetite;

• headache; or

• mild skin rash or itching.

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect.

For Healthcare Professionals

Applies to rifabutin: oral capsule

General

Rifabutin was generally well tolerated in clinical trials. Discontinuation due to a side effect was reported in 16% of patients taking rifabutin (the active ingredient contained in Mycobutin) compared to 8% of patients taking placebo. Discontinuation of rifabutin was mainly due to rash (4%), gastrointestinal intolerance (3%), and neutropenia (2%).

Hematologic

Neutropenia and thrombocytopenia have been associated with rifabutin (the active ingredient contained in Mycobutin) use. However, the latter may be related to underlying disease since it has been observed at a similar rate in control groups in placebo-controlled trials.

Hematologic side effects have included neutropenia (less than 750/mm3; 25%), leukopenia (less than 1500/mm3; 17%), anemia (less than 8 g/dL; 6%), thrombocytopenia (less than 50,000/mm3; 5%), eosinophilia (1%), and hemolysis (less than 1%). At least one case of thrombotic thrombocytopenic purpura has been reported.

Dermatologic

Dermatologic side effects have included rash (11%) and skin discoloration (less than 1%). Perspiration and skin may be discolored brown-orange with rifabutin (the active ingredient contained in Mycobutin) and some of its metabolites. At least one case of acute generalized exanthematous pustulosis has been reported.

Gastrointestinal

Gastrointestinal side effects have included nausea (6%), nausea and vomiting (3%), dyspepsia (3%), diarrhea (3%), eructation (3%), anorexia (2%), flatulence (2%), vomiting (1%), and Clostridium difficile associated diarrhea. Feces and saliva may be discolored brown-orange with rifabutin (the active ingredient contained in Mycobutin) and some of its metabolites. Aphthous stomatitis has rarely been reported.

Ocular

Ocular side effects have included uveitis, resulting in itching, decreased vision, photophobia, pain, and temporary blindness in some patients. Uveitis was reported at doses from 1050 mg/day to 2400 mg/day. Tears may be discolored brown-orange with rifabutin (the active ingredient contained in Mycobutin) and some of its metabolites. Soft contact lenses may be permanently stained.

Uveitis was rare when rifabutin was used as a single agent at 300 mg/day, even in combination with fluconazole and/or macrolides. However, the incidence of uveitis was greater if higher doses of rifabutin were used with these agents. Patients who developed uveitis had mild to severe symptoms that resolved following therapy with corticosteroids and/or mydriatic eye drops; however, in some severe cases, resolution of symptoms occurred after several weeks.

Hepatic

Hepatic side effects have included increased SGPT (greater than 150 units/L; 9%), increased SGOT (greater than 150 units/L; 7%), and hepatitis (less than 1%).

Other

Three cases of drug-induced lupus syndrome (DILS) have been reported. All cases were receiving standard doses of rifabutin (the active ingredient contained in Mycobutin) and all had positive antinuclear antibodies during their lupus-like reactions. Symptoms of DILS included malaise, myalgias, arthralgias, and fever. None of the cases experienced lupus-type nephritis or skin and CNS involvement.

Other side effects have included abdominal pain (4%), taste perversion (3%), fever (2%), asthenia (1%), chest pain (1%), pain (1%), and influenza-like syndrome. Sputum may be discolored brown-orange with rifabutin and some of its metabolites. Drug-induced lupus syndrome has been reported.

Nervous system

Nervous system side effects have included headache (3%), insomnia (1%), seizure, paresthesia, aphasia, and confusion.

Musculoskeletal

Musculoskeletal side effects have included myalgia (2%), arthralgia (less than 1%), myositis (less than 1%), and polyarthralgia-arthritis syndrome (rare). Generalized arthralgia was reported at doses from 1050 mg/day to 2400 mg/day.

In one study of 10 patients receiving greater than 1 gram of rifabutin per day, nine developed significant distal, small joint arthralgias. No evidence of concomitant rheumatic disease was evident and no effusions were observed.

Cardiovascular

Cardiovascular side effects have included nonspecific T wave changes on electrocardiogram.

Metabolic

Metabolic side effects have included increased alkaline phosphatase (greater than 450 units/L; less than 1%).

Respiratory

Respiratory side effects have included chest pressure or pain with dyspnea in less than 1% of patients.

Genitourinary

Urine may be discolored brown-orange with rifabutin (the active ingredient contained in Mycobutin) and some of its metabolites.

Genitourinary side effects have included urine discoloration (30%).

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