Efavirenz use while Breastfeeding | Drugs.com
Drug LevelsMaternal Levels. Thirteen mothers who averaged 15.8 weeks (range 6 to 25 weeks) postpartum were treated with efavirenz 600 mg daily plus zidovudine and lamivudine. Milk and plasma samples were taken 3 to 4 hours after the last dose. Skimmed breastmilk efavirenz concentrations averaged 3.5 mg/L (range 1.3 to 7.4 mg/L).[3]Five mothers who were taking oral efavirenz 600 mg daily as part of an antiretroviral regimen collected mid-feed milk samples at 0.5, 1, 2, 4, 8, 12 and 24 hours after an evening dose at an average of 146 days after delivery. The average peak level of 4.5 mg/L occurred at about 4 hours after the dose and the average trough milk value was 2.5 mg/L.[4]One hundred thirty-four mothers who were taking efavirenz 600 mg at bedtime as part of their antiretroviral regimen and their infants were studied. In the first part of the study, women were separated into noncarriers, homozygotes and homozygotes for the CYP2B6 516TT gene. Random breastmilk concentrations had medi...