Second-Line Injectable Drugs for the Treatment of Multidrug-Resistant Tuberculosis: Why do We Keep Using Them?

ABSTRACT

Second-line injectable drugs (kanamycin, amikacin and capreomycin) have been an integral part of the multidrug-resistant tuberculosis (MDR-TB) treatment regimen for decades, despite their known association with renal failure and ototoxicity. Unfortunately, there are many countries that haven't included new or reused drugs in their treatment regimens for MDR-TB and still depend on second-line injectable drugs (SLIDs) in order to have a sufficient amount of effective drugs in their regimens. Our purpose is to show the frequency and severity of the ototoxicity associated with the use of SLIDs only detected initially by means of an audiometry. We conducted a retrospective analysis including all the patients who received treatment regimens with SLIDs from 2010 to 2017 in a tuberculosis clinic in Mexico. 47 patients who received SLIDs (amikacin, kanamycin, capreomycin) were included in the analysis. The mean age was 40.3 ± 16.4 years. Thirty one patients (63.3%) had previously received TB treatment in the past. The most commonly used SLID was amikacin in 33 cases (67.3%), followed by capreomycin in 14 cases (28.6%). Twenty seven patients (55.1%) developed significant hearing loss (> 40 dB), and 13 patients (26.5%) developed severe or profound hearing loss (> 70 dB). Severe hearing loss is a common, irreversible and now unnecessary complication of the MDR/RR-TB (multidrug- and rifampicin-resistant tuberculosis) treatment, since the SLIDs may and shall be substituted by new and reused, more effective and far less toxic drugs.