Five-year follow-up of a clinical trial of three 6-month regimens of chemotherapy given intermittently in the continuation phase in the treatment of pulmonary tuberculosis. Singapore Tuberculosis Service/British Medical Research Council

Am Rev Respir Dis. 1988 May;137(5):1147-50. doi: 10.1164/ajrccm/137.5.1147.


In a study in Singapore, patients of Chinese, Malay, and Indian ethnic origin with sputum-smear-positive pulmonary tuberculosis were allocated at random to daily treatment with streptomycin, isoniazid, rifampin, and pyrazinamide for 2 months (2SHRZ), for 1 month (1SHRZ), or for 2 months without streptomycin (2HRZ), followed, for all patients, by 3-times-weekly isoniazid and rifampin (H3 R3) up to 6 months. As previously reported, all except 1 of 319 patients with drug-susceptible tubercle bacilli pretreatment had a favorable bacteriologic status at the end of chemotherapy, and among the 300 patients assessed up to 30 months (24 months after the end of chemotherapy), there was only 1 bacteriologic relapse in each series, giving an overall therapeutic failure rate of only 1.3%. Follow-up has been continued at 6-month intervals up to 5 yr. During the 5 yr, the total relapse rate for patients with drug-susceptible strains pretreatment was 2.4% of 297 patients (95% confidence limits, 1.0 to 4.8%). Among the 31 patients with strains resistant to isoniazid, streptomycin, or both drugs pretreatment, there were no failures during chemotherapy and 4 (13%) subsequent relapses.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antitubercular Agents / administration & dosage*
  • Drug Administration Schedule
  • Drug Resistance, Microbial
  • Drug Therapy, Combination
  • Follow-Up Studies
  • Humans
  • Isoniazid / administration & dosage
  • Isoniazid / therapeutic use
  • Mycobacterium tuberculosis / drug effects
  • Pyrazinamide / administration & dosage
  • Pyrazinamide / therapeutic use
  • Recurrence
  • Rifampin / administration & dosage
  • Rifampin / therapeutic use
  • Streptomycin / administration & dosage
  • Streptomycin / therapeutic use
  • Tuberculosis, Pulmonary / drug therapy*
  • Tuberculosis, Pulmonary / microbiology


  • Antitubercular Agents
  • Pyrazinamide
  • Isoniazid
  • Rifampin
  • Streptomycin