Treatment of Tuberculosis: Susceptible Strains

The treatment of susceptible tuberculosis has evolved in the last 70 years, from requiring the use of toxic drugs (PAS, streptomycin by parenteral route) for two years, to exclusively oral treatment, with a combination of more effective and less toxic medications for six months. The cure rate with this regimen that includes isoniazid, rifampicin, ethambutol, and pyrazinamide is higher than 90% when the patient is adherent and completes the treatment. Hence, this indicates the importance of directly observed treatment (DOT), a strategy focused on the patient.

It is essential before starting treatment with first-line drugs to demonstrate that the strain causing the condition is susceptible to isoniazid and rifampin; nowadays, these results can be available in 24-48 hours by molecular methods, avoiding the delay associated with phenotypic methods.

Although the reduction from 24 to 6 months is significant, it is still a very prolonged treatment that favors the loss of follow-up. Unfortunately, attempts to reduce the duration to four months by the addition of fluoroquinolones did not have favorable results, and the recommended length is still six months.

The most recent recommendations of the WHO include the daily administration of the drugs for six months (instead of intermittent administration during the last four months of the regimen) and the administration of the four drugs in a combined fixed dose presentation.

Keywords: DOY, Drug-susceptible, Ethambutol, Isoniazid, Pyrazinamide, Rifampin, Tuberculosis.DOY, Drug-susceptible, Ethambutol, Isoniazid, Pyrazinamide, Rifampin, Tuberculosis.