Serum concentrations of antimycobacterial drugs in patients with pulmonary tuberculosis in Botswana.
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.
Tappero
Jordan W
JW
Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
Bradford
Williamson Z
WZ
Agerton
Tracy B
TB
Hopewell
Philip
P
Reingold
Arthur L
AL
Lockman
Shahin
S
Oyewo
Aderonke
A
Talbot
Elizabeth A
EA
Kenyon
Thomas A
TA
Moeti
Themba L
TL
Moffat
Howard J
HJ
Peloquin
Charles A
CA
D000328:Adult; D000995:Antitubercular Agents / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D001902:Botswana; D015897:Comorbidity; D004977:Ethambutol / Q000493:pharmacokinetics; D005260:Female; D015658:HIV Infections / Q000150:complications; D006801:Humans; D007538:Isoniazid / Q000493:pharmacokinetics; D008297:Male; D011718:Pyrazinamide / Q000493:pharmacokinetics; D012293:Rifampin / Q000493:pharmacokinetics; D014397:Tuberculosis, Pulmonary / Q000097:blood / Q000150:complications / Q000188:drug therapy*
D000995:Antitubercular Agents; D011718:Pyrazinamide; D004977:Ethambutol; D007538:Isoniazid; D012293:Rifampin