Abstract
Introduction: Therapeutic drug monitoring (TDM) is the process of adjusting drug dosages based on serum concentration data. Several reports have shown altered pharmacokinetic profiles for the anti-tuberculosis (TB) drugs in HIV patients. Such patients may benefit from TDM and early interventions may prevent the development of further drug resistance.
Aims: This study aimed to determine serum isoniazid (INH), rifampin (RIF), and pyrazinamide (PZA) concentrations in a cohort of patients with HIV-related TB who were treated in a referral TB center.
Methods: Twenty HIV-infected patients who received 4 first-line anti-TB drugs for active TB were eligible for the study. Venous blood was obtained 2 h after daily dose of INH (5mg/kg), RIF (10 mg/kg), and PZA (25 mg/kg). Serum levels of anti-TB drugs were analyzed using high –pressure liquid chromatography (HPLC) and compared with published normal ranges.
Results: Of the 20 patients (mean age 36.25 years, range 30-57 years), 18 (90%) had a very low maximum concentration of INH (<1 µg/mL), and 2 (10%) had a low maximum concentration of INH (<2 µg /mL). All patients had a very low maximum concentration of RIF (<7 µg /mL) and 7 (35%) had a low maximum concentration of PZA (<20 µg /mL).
Conclusions: Low serum concentrations of INH, RIF, and PZA, which may be related to malabsorption, are common in HIV-infected TB patients. TDM of anti-TB drugs may helps clinicians to optimize drug therapy and improve TB cure rates.
- © 2012 ERS
