Isoniazid/acetylisoniazid urine concentrations: markers of adherence to isoniazid preventive therapy in children

Abstract

The Arkansas colorimetric method monitors adherence to isoniazid (INH) by the detection of INH metabolites in urine. Urine samples 4 h after INH administration in 31 human immunodeficiency virus infected children receiving daily or thrice weekly INH preventive therapy were Arkansas test-positive for 29/31 (94%), while acetylisoniazid (AcINH) was detected in 30/31 (97%) using mass spectrometry. At 24, 48 and 72 h, only 78%, 23% and 0 samples, respectively, were Arkansas-positive, while INH or AcINH was detected in respectively 94%, 69% and 33%. The Arkansas test reliably predicted INH ingestion at a clinic visit 4 h after morning doses, but did not perform well at 24 h.

Trial registration: ClinicalTrials.gov NCT00330304.

Conflict of interest statement

Conflict of interest: none declared.

Figures

Figure

Bar chart showing colours observed from the Arkansas test and their occurrence in percentage at different sampling times in the 31 children assigned to daily or intermittent isoniazid. The 4 h result is a combination of the daily and intermittent arms, which had 18 and 13 samples, respectively.