Severe neutropenia caused by recommended prophylactic doses of rifabutin

Rifabutin Containing Triple Therapy and Rifabutin with Bismuth Containing Quadruple Therapy for Third‐Line Treatment of Helicobacter pylori Infection: Two Pilot Studies

“…Due to the reported myelotoxicity (with leukopenia and thrombocytopenia) of RIF, a blood cell count was performed in all patients at baseline and after 5 days of treatment [28,29].…”

Rifabutin‐based Helicobacter pylori eradication ‘rescue therapy’

“…However, one patient withdrew after 6 days of therapy: he developed fever with a severe leukopenia and trombocytopenia that continued for several days after discontinuation of rifabutin. His absolute WBC count fell below 2000/mm 3 , and his platelet count fell below 100 000/mm 3 at day 7. His bone marrow aspirate indicated that neutropenia was a result of myelotoxicity.…”

“…The myelotoxicity of rifabutin has been described during longer exposure (> 10 days) and at a higher dosage (> 600 mg/day). 2,3 Important drug interactions with commonly-used antibiotics can also be speculatedÐfor example, with clarithromycin in combination therapy, because rifabutin induces cytochrome P-450. 4 Finally, since the Italian Ministry of Health and the FDA indications for the use of rifabutin are restricted to prevention or cure of Mycobacterium avium complex disease in HIV-infected patients, the use of this drug outside this indication is questionable.…”

Severe neutropenia among healthy volunteers given rifabutin in clinical trials

“…Rifabutin is a medication approved by the Food and Drug Administration for the prevention of disseminated Mycobacterium avium complex infections in patients with acquired immunodeficiency syndrome. In a clinical trial conducted in 1995 and published in 1996 and 1998, thrombocytopenia and severe neutropenia (grade 4, absolute neutrophil counts <500 cells/mm 3 ) occurred among healthy volunteers receiving a standard dose of 300 mg/d of this drug 1 , 2 . The 14‐day study was terminated after 10 days because of neutropenia, fevers as high as 103.0°F, and other adverse events.…”