Plasma Clearance of Nevirapine Is Increased in Neonates of Mothers Treated with Nevirapine during Pregnancy

G. P. TAYLOR*¹, D. BACK², E. G. H. LYALL¹, C. STAINSBY¹, A. DE RUITER³, G. TUDOR-WILLIAMS¹, and J. N. WEBER¹. ¹Imperial Coll. Sch. of Med., London, UK; ²Univ. of Liverpool, UK; and ³St. Thomas's Hosp., London, UK

Background: Adequate concentrations of nevirapine (>100 ng/ml plasma) have been demonstrated for up to 7 days following a single maternal 200mg dose given in labour followed by a single 2mg/kg dose to the neonate age 48-72 hours. In our centre, Combivir plus nevirapine is commonly prescribed during the second and third trimesters to pregnant women with high plasma HIV load. As the pharmacokinetics of nevirapine in pregnancy have not been described we have monitored steady state concentrations in mothers and their neonates.
Subjects: 18 women taking nevirapine during pregnancy and their infants.
Methods Plasma separated from heparinised whole blood, stored at -20 C. Plasma nevirpaine concentration determined by High Performance Liquid Chromatography.


Discussion: The steady state plasma concentrations of nevirapine in the mothers are similar to those reported in non-pregnant adults and higher than with a single nevirapine dose (1710ng/ml) Although the cord and neonate plasma concentrations at 24 hours are consequently higher (2580 ng/ml v 1390 ng/ml) they have declined by 36% within the first 24 hours. Samples from later timepoints have been collected but further studies are required to determine the optimal regimen in these circumstances.

Key Words: Pharmacokinetics, Nevirapine, Pregnancy

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