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J Pediatric Infect Dis Soc. 2016 Dec;5(4):356-365. Epub 2015 May 26.

Pharmacokinetics of First-Line Antituberculosis Drugs Using WHO Revised Dosage in Children With Tuberculosis With and Without HIV Coinfection.

Author information

1
Department of Medicine, Warren Alpert Medical School of Brown University, Providence, Rhode Island.
2
Department of Medicine, The Miriam Hospital, Providence, Rhode Island.
3
Directorate of Child Health, Komfo Anokye Teaching Hospital, Kumasi, Ghana.
4
Department of Child Health, School of Medical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
5
Department of Biostatistics and Computational Biology, University of Rochester School of Medicine and Dentistry, New York.
6
Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, South Africa.
7
College of Pharmacy and Emerging Pathogens Institute, University of Florida, Gainesville.

Abstract

BACKGROUND:

Pharmacokinetic data on the first-line antituberculosis drugs using the World Health Organization (WHO) revised dosages for children are limited. We investigated the pharmacokinetics of these drugs in children who were mostly treated with revised dosages.

METHODS:

Children with tuberculosis on first-line therapy for at least 4 weeks had blood samples collected at predose, 1, 2, 4, and 8 hours postdose. Drug concentrations were determined by validated liquid chromatography mass spectrometry methods, and pharmacokinetic parameters were calculated using noncompartmental analysis. Factors associated with plasma peak concentration (Cmax) and the area under the time-concentration curve 0-8 hours (AUC0-8h) of each drug was examined using univariate and multivariate analysis.

RESULTS:

Of the 62 children, 32 (51.6%) were male, 29 (46.8%) were younger than 5 years old, and 28 (45.2%) had human immunodeficiency virus (HIV) coinfection. Three patients had undetectable pyrazinamide and ethambutol concentrations. The median (interquartile range) AUC0-8h for isoniazid was 17.7 (10.2-23.4) µg·h mL-1, rifampin was 26.0 (15.3-36.1) µg·h mL-1, pyrazinamide was 144.6 (111.5-201.2) µg·h mL-1, and ethambutol was 6.7 (3.8-10.4) µg·h mL-1. Of the children who received recommended weight-band dosages, 44/51 (86.3%), 46/56 (82.1%), 27/56 (48.2%), and 21/51 (41.2%) achieved target Cmax for isoniazid, pyrazinamide, ethambutol, and rifampin, respectively. In multivariate analysis, age, sex, HIV coinfection status, and drug dosage in milligrams per kilogram were associated with the drugs' plasma drug Cmax or AUC0-8h.

CONCLUSIONS:

The revised dosages appeared to be adequate for isoniazid and pyrazinamide, but not for rifampin or ethambutol in this population. Higher dosages of rifampin and ethambutol than currently recommended may be required in most children.

KEYWORDS:

children; first-line antituberculosis drugs; pharmacokinetics; revised WHO dosage; tuberculosis

PMID:
26407268
PMCID:
PMC5181357
DOI:
10.1093/jpids/piv035
[Indexed for MEDLINE]
Free PMC Article

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