Evaluation of saliva as an alternative matrix for monitoring plasma Zidovudine, Lamivudine and nevirapine concentrations in Rwanda.

Saliva may provide interesting advantages as matrix for compliance measurements, pharmacokinetic studies and therapeutic drug monitoring in resource limited countries. We investigated the feasibility of using saliva for compliance monitoring of zidovudine (ZDV), lamivudine (3TC) and nevirapine (NVP) in 29 HIV-1 infected patients from Rwanda. ZDV, 3TC and NVP drug levels were quantified by an LC/MS-MS method in plasma and stimulated saliva samples and compared using Bland-Altman analysis. Seven patients demonstrated undetectable saliva ZDV levels while five out of these seven also showed no 3TC salivary concentrations. For the other samples, we observed a good agreement between salivary and plasma concentrations of each antiretroviral drug. A significant relation between the difference in saliva and plasma ZDV concentrations and the average ZDV concentration in the two matrices was deduced as follow: y = -380.15 + 1.79 x. The log saliva and plasma concentration difference of both 3TC and NVP was consistent across the range of average log concentration. Overall, we showed large agreement limits suggesting a wide inter patient variability that may result to non-reliable plasma level predictions from saliva drug measurements. Therefore, our results indicate that saliva may serve as a valuable tool only for NVP compliance testing because of its high salivary concentration.

Efavirenz in human breast milk, mothers', and newborns' plasma.

BACKGROUND AND METHODS: Highly active antiretroviral therapy with efavirenz (EFV) has been prescribed to HIV-positive pregnant women in Rwanda (HIV status 1 and CD4 cell count > 350 cells/mm) during the last trimester of pregnancy and for 6 months after delivery. The EFV concentrations in maternal plasma, breast milk and in newborns' plasma of 13 women and their children between 6 weeks and 6 months post partum are reported. RESULTS: Results show a mean EFV plasma concentration of 6.55 mg/L in maternal plasma, 3.51 mg/L in skim milk, and 0.85 mg/L in infant plasma. Significant linear correlations between maternal plasma and skim milk (r = 0.8666, P < 0.0001) and between skim milk and infant plasma (r = 0.6646, P < 0.02) were found, but no significant correlation was observed between maternal and infant plasma concentrations (P > 0.05). CONCLUSIONS: After 6 months of breast-feeding, no child out of the 13 had been infected with HIV and all had good psychomotor and growth development. Our results suggest that EFV may be an alternative to nevirapine (NVP) during the third trimester of pregnancy and during the breast-feeding period. Further studies on larger groups of newborns will be necessary to get a better understanding of possible prophylactic protection of the newborns by highly active antiretroviral therapy with EFV given to the mothers.