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- Page navigation anchor for RE: Responsible use of rifampin for the treatment of latent tuberculosis infectionRE: Responsible use of rifampin for the treatment of latent tuberculosis infection
To the Editor,
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We read with interest the recent commentary by Batt and Khan in the CMAJ about our recent publications of trials comparing 4 months Rifampin (4R) with 9 months isoniazid (9H) in adults 1 and children2. In those two trials, and an earlier trial among adults3, we have shown that 4R is consistently significantly superior to 9H for completion and safety in adults and is very safe and well tolerated in children. In both populations, efficacy of 4R was non-inferior to that of 9H 1,2. In summary, 4R is shorter, safer, better completed and as effective as 9H. Seems like an easy choice for patients and providers.
However, Batt and Khan raise concerns regarding the potential risk of creating Rifampin resistance if 4R is given to patients with undetected active TB. We agree that creation of resistance by inadvertent mono-therapy of active TB is a very important potential risk, but we believe it is important to adequately review the available evidence regarding this risk. There have been 2 relevant systematic reviews: The first, cited by the author , reviewed 6 studies of rifamycin-containing regimens and found no evidence of increased risk of acquired rifampin resistance 4. The second reviewed 13 studies, including 6 among HIV-infected persons, and found no evidence of increased risk of acquired resistance to INH in randomized trials or cohort studies using INH to treat latent TB 5. This evidence suggests that risk of acquired drug resistance from latent TB...Competing Interests: None declared. - Page navigation anchor for Responsible use of Rifampin in Canada is threatened by irresponsible shortagesResponsible use of Rifampin in Canada is threatened by irresponsible shortages
We agree wholeheartedly with Batt and Khan’s description of rifampin as “unequivocally the most important drug in the global fight against TB” (1). However, using a drug effectively requires that it be available in the first place. Disturbingly, rifampin is becoming increasingly difficult to acquire in Canada, with both companies (Sanofi-Aventis and Bausch Health) who sell it facing long-term shortages, and the imminent potential for indefinite total stockouts (2). Rifampin is the cornerstone of care for active TB disease, forming part of all first-line treatment regimens (3) as well as a valuable treatment for latent TB infection. These shortages of rifampin pose a real threat to TB care (4) in Canada, including the prevention and treatment of active TB in the Indigenous communities most affected by the disease (5).
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The Government of Canada has consistently failed to offer adequate long-term solutions and short-term fixes for frequent drug shortages (6). For past shortages of other basic TB drugs like ethambutol, existing mechanisms like the Special Access Programme (SAP) have not proven to be effective stop-gap measures. And although the new Access to Drugs in Exceptional Circumstances mechanism, which allows temporary access to drugs without market authorization in Canada in response to an urgent public health need, has proven helpful in accessing rifapentine (7), another drug for latent TB infection, its usefulness in addressing shortages of drugs that are alrea...Competing Interests: None declared.