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Predose Infant Nevirapine Concentration With the Two-Dose Intrapartum Neonatal Nevirapine Regimen: Association With Timing of Maternal Intrapartum Nevirapine Dose

Mirochnick Mark; Dorenbaum, Alejandro; Blanchard, Suzette; Cunningham, Coleen K.; Gelber, Richard D.; Mofenson, Lynne; Culnane, Mary; Sullivan, John L.
JAIDS Journal of Acquired Immune Deficiency Syndromes: June 1st, 2003

Objective:To evaluate cord blood and predose nevirapine concentrations in infants exposed to the two-dose intrapartum neonatal nevirapine regimen.

Methods:The authors obtained plasma samples for nevirapine assay from cord blood and just prior to the 48-hours to 72-hours after birth neonatal nevirapine dose from a subset of infants participating in PACTG 316, a randomized, placebo-controlled trial of the two-dose intrapartum neonatal nevirapine regimen added to standard antiretroviral therapy.

Results:Nevirapine concentrations were measured in 109 cord blood samples and 149 predose samples. Cord blood nevirapine concentrations were below the target concentration of 100 ng/mL (10-times the in vitro IC50 of nevirapine against wild-type HIV) in eight (7%) of 109 infants (95% confidence interval [CI], 3%-14%); the concentrations in six of these infants were below the assay limit of quantitation. Predose infant nevirapine concentrations were below 100 ng/mL in 23 (15%) of 149 infants (95% CI, 10%-22%); the concentrations in 13 of these infants were below the assay limit of quantitation. Lower predose nevirapine concentrations were associated with lower cord blood concentrations and a shorter interval between maternal dosing and delivery. All but one of the infants with predose nevirapine concentrations below the assay limit of quantitation were born less than 2 hours after maternal dosing.

Conclusion:Infants born less than 2 hours after maternal nevirapine dosing during labor should receive a dose of nevirapine immediately after birth in addition to the standard infant dose at 48 to 72 hours.

Address correspondence and reprint requests to Mark Mirochnick, MD, Boston Medical Center, 91 East Concord Street, 6th Floor, Boston, MA 02118. E-mail:

Manuscript received January 14, 2003; accepted March 19, 2003.

© 2003 Lippincott Williams & Wilkins, Inc.