BACKGROUND: Therapeutic drug monitoring (TDM) has been advocated to promote the efficacy of antituberculosis agents. Cycloserine (CS) is a second-line anti-tuberculosis drug whose serum concentrations in tuberculosis (TB) patients are largely unknown. OBJECTIVES: To investigate serum CS concentrations after drug ingestion in TB patients. METHODS: Multidrug-resistant TB patients who were taking CS in a tertiary care centre in northern Taiwan between 1 April 2009 and 31 October 2009 were enrolled in the study. Serum CS concentrations were measured at 2 and 6 h after drug administration. RESULTS: Of 32 patients enrolled, 23 were males and 9 females. The mean CS dose was 8.8 ± 1.3 mg/kg. The mean serum concentrations at 2 and 6 h were respectively 19.7 ± 8.3 and 18.1 ± 8.7 μg/ml. Seven patients (22%) had serum drug concentrations that were higher at 6 h than at 2 h, 12 (38%) had peak serum concentrations within the recommended range of 20-35 μg/ml; 18 patients (56%) had concentrations 35 μg/ml. CONCLUSION: Lower than recommended serum CS concentrations and delayed absorption were common. It is essential to develop practical TDM to maintain proper serum drug concentrations.

Original languageEnglish
JournalInternational Journal of Tuberculosis and Lung Disease
Issue number5
Publication statusPublished - May 1 2014


  • Cycloserine
  • MDR-TB
  • Therapeutic drug monitoring
  • Tuberculosis

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Infectious Diseases
  • Medicine(all)


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