SAFETY ASSESSMENT OF EFAVIRENZ AFTER A SINGLE???DOSE BIOEQUIVALENCE STUDY: A TREND TO CORRELATE CENTRAL NERVOUS SYSTEM EFFECT AND PLASMA CONCENTRATION

Marta Vázquez*, Pietro Fagiolino, Manuel Ibarra, Laura Magallanes

The objective of the current study was to examine safety and pharmacokinetic data obtained from a bioequivalence study of two brands of efavirenz carried out in healthy volunteers in order to assess the relationship between concentrations and appearance of adverse events. Drowsiness was reported in almost all the subjects 1 or 2 hours post dosing and generally the onset of this adverse event was 30 or 40 minutes before high efavirenz plasma concentrations, evidencing a lag time between venous plasma concentration and effect. As many studies reported, arterial drug concentration is higher than the respective venous concentration during drug inputs so adverse events experienced during drug input would correlate with arterial drug concentration rather than the respective venous concentration.