Single dose pharmacokinetics of Efavirenz in health Indian subjects.

Ramachandran, G.; Hemanth Kumar, A.K.; Sukumar, B.; Kumaraswami, V.; Swaminathan, S.

Journal of Tuberculosis, Lung Disease and HIV/AIDS; 2007; IV; 38-43.

Abstract: Background & Objective: Access to antiretroviral therapy in India is improving. Efavirenz (EFV) is a commonly used non-nucleoside reverse transcriptase inhibitor used to treat HIV infection. No information is available on the pharmacokinetics of EFV in Indian subjects. The aim of this study was to obtain information on single dose pharmacokinetics of efavirenz (EFV) in healthy Indian subjects.

Methods: Sixteen adult healthy volunteers (8 males and 8 females) were administered a single oral tablet of 600 mg EFV after an overnight fast. Blood samples were collected at 1, 2, 3, 4, 5, 6, 10, 24 and 48 hours post dosing. Plasma EFV concentrations were estimated by HPLC, and certain pharmacokinetic variables were calculated.

Results: Plasma EFV concentrations were higher in females than males at all the time points, the differences being significant at 1 ( p<0.001 ) and 2 ( p=0.05 ) hours. Females had significantly higher peak concentration (C max ) of EFV than males ( p=0.05 ) (3.11 & 1.90 µg/ml). The inter-individual variability in C max and AUC 0-48 were 42 and 45% respectively.

Conclusions: This study provides basic information on the pharmacokinetics of EFV in Indian subjects. Females had higher peak levels of EFV than males. Inter-subject variability was high. Further studies are necessary to describe the pharmacokinetic profile of EFV under steady state conditions in Indian patients on antiretroviral treatment.

Keywords: Efavirenz, HIV infection, pharmacokinetics, Indian subjects

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