Isoniazid concentrations in hair and plasma area-under-the-curve exposure among children with tuberculosis.

We measured hair and plasma concentrations of isoniazid among sixteen children with tuberculosis who underwent personal or video-assisted directly observed therapy and thus had 100% adherence. This study therefore defined typical isoniazid exposure parameters after two months of treatment among fully-adherent patients in both hair and plasma (plasma area under the concentration-time curve, AUC, estimated using pharmacokinetic data collected 0, 2, 4, and 6 hours after drug administration). We found that INH levels in hair among highly-adherent individuals did not correlate well with plasma AUC or trough concentrations, suggesting that each measure may provide incremental and complementary information regarding drug exposure in the context of TB treatment.

Source Case Investigation for Children with TB Disease in Pune, India.

Setting. Contact tracing is broadly encouraged for tuberculosis (TB) control. In many high-burden countries, however, little effort is made to identify contacts of newly diagnosed TB patients. This failure puts children, many of whom live in poor crowded communities, at special risk. Objectives. To perform source-case investigations for 50 pediatric TB cases in Pune, India. Design. A descriptive cross-sectional observational study of pediatric TB cases < 5 years of age. Information was collected about the index case and household contacts. Results. In 15 (30%) of the 50 pediatric index cases, the household contained known TB contacts, 14 (86%) of whom were adults. Prior to their own diagnosis of TB, only one of the 15 pediatric index cases who met criteria for isoniazid preventive therapy received it. The index cases with known household TB contacts had a longer delay in initiating TB treatment than those without TB contacts (17.5 versus 2 days; P = 0.03). Use of contact tracing identified 14 additional household TB suspects, 8 (57%) of whom were children. Conclusions. This study identified missed opportunities for TB prevention, as contact tracing is poorly implemented in resource-limited countries, like India. Further strategies to improve the implementation of TB prevention, especially in young children, are urgently needed.