Saliva as an alternative body fluid for therapeutic drug monitoring of thenonnucleoside reverse transcription inhibitor nevirapine

The objective of this study was to evaluate the applicability of saliva as an alternative body fluid for therapeutic drug monitoring of nevirapine. Th e pharmacokinetics of nevirapine in plasma and saliva during a dosing inter val was assessed in HIV-1-infected patients taking nevirapine (200 mg twice daily) to explore the relation between the concentration of nevirapine in plasma and saliva. To validate the anticipated relationship prospectively, single, paired plasma and saliva samples were obtained from nevirapine-trea ted HIV-1-infected outpatients. The plasma nevirapine concentration was str ongly correlated with the salivary concentration. The mean saliva/plasma co ncentration ratio was 0.51 and was independent of the time after ingestion. Salivary nevirapine concentrations were used to estimate the corresponding plasma concentrations for 31 outpatients. Compared with the true plasma co ncentrations, the estimated concentrations were biased by -4.2%, with a pre cision of 13.3%. These data show a strong correlation between the salivary and plasma concentrations of nevirapine at a dosage of 200 mg twice daily. This relation has been validated prospectively, and the prediction of plasm a concentrations was accurate and precise. Therefore, the authors conclude that saliva can be a useful body fluid for therapeutic drug monitoring of n evirapine.