Serum concentrations of antimycobacterial drugs in patients with pulmonary tuberculosis in Botswana

Clin Infect Dis. 2005 Aug 15;41(4):461-9. doi: 10.1086/431984. Epub 2005 Jul 8.

Abstract

Background: We conducted a pharmacokinetic study of antimycobacterial drugs involving a cohort of patients with pulmonary tuberculosis (TB) in Gaborone, Botswana, to assess the prevalence of and risk factors for low drug concentrations in serum.

Methods: Adults participated if they had a history of cough > or =2 weeks, had abnormal chest radiograph findings, consented to testing for human immunodeficiency virus (HIV), had sputum cultures positive for Mycobacterium tuberculosis, and were receiving antituberculous therapy for >7 days. Observed maximum serum concentrations were compared with published normal ranges. RESULTS. Of 91 patients enrolled, 89 (98%) were outpatients, and 59 (68%) of 87 patients tested had HIV infection. The following numbers of patients had low serum concentrations of the following drugs: isoniazid, 27 (30%) of 90; rifampin, 71 (78%) of 91; ethambutol, 37 (41%) of 91; and pyrazinamide, 1 (1%) of 91. Low serum concentrations of both isoniazid and rifampin occurred in 23 (26%) of 90 patients. Low serum concentrations of rifampin were found in both HIV-infected and non-HIV-infected patients, and such patients were less likely to have >4 weeks of symptoms, more likely to have lymphadenopathy, and more likely to have low serum albumin levels (P<.05 for all). The associations with noncavitary pulmonary disease (P=.12) and HIV infection (P=.07) did not reach statistical significance. Delayed absorption was most common with ethambutol, followed by rifampin.

Conclusions: These data, predominantly from HIV-infected patients with TB, suggest that low isoniazid, rifampin, and ethambutol concentrations are common in Botswana. In contrast, pyrazinamide usually is well absorbed.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Antitubercular Agents / blood
  • Antitubercular Agents / pharmacokinetics*
  • Antitubercular Agents / therapeutic use
  • Botswana
  • Comorbidity
  • Ethambutol / pharmacokinetics
  • Female
  • HIV Infections / complications
  • Humans
  • Isoniazid / pharmacokinetics
  • Male
  • Pyrazinamide / pharmacokinetics
  • Rifampin / pharmacokinetics
  • Tuberculosis, Pulmonary / blood
  • Tuberculosis, Pulmonary / complications
  • Tuberculosis, Pulmonary / drug therapy*

Substances

  • Antitubercular Agents
  • Pyrazinamide
  • Ethambutol
  • Isoniazid
  • Rifampin