Publication

Abstract : Altered pharmacokinetics of anti tuberculosis drugs may contribute to an increased risk of tuberculosis treatment failure for TB population.Here we examined and compared the pharmacokinetics of rifampicin and isoniazid in the intensive and continuation phase of tuberculosis treatment.Previously we found that rifampicin and isoniazid exposure was lower in intensive phase treatment when compared to continuation phase. For the study purpose 25 patients each from intensive and continuation phase were included in a government hospital setting. Pharmacokinetic sampling was performed for rifampicin and isoniazid in patients after light breakfast. The assessments were done for 50 tuberculosis patients after careful observation. There is much differences in the area under the concentration- time curves of drugs in plasma from 0 to 8 h(AUC0-8),maximum concentrations of drug in plasma (C max),the time to C max, and half-lives of Rifampicin, Isoniazid were found between intensive and continuation phase tuberculosis treatment. Biological half life of both rifampicin and isoniazid was lowered in both phases of treatment leaving a short exposure of drug.Compared to continuation phase AUC(0-8hrs) of rifampicin was less in intensive phase (32.005μg hr/ml, P= 0.0266), and AUC of isoniazid also less in intensive phase when compared to continuation phase (35.57μg hr/ml,p=0.1354). The study reveals that there is reduced exposure to rifampicin and isoniazid in intensive phase ,compared to continuation phase. This could be one of the reason for relapse or recurrence of TB.