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Abacavir / lamivudine Pregnancy and Breastfeeding Warnings

Abacavir / lamivudine is also known as: Epzicom

Abacavir / lamivudine Pregnancy Warnings

Animal studies with abacavir (high-dose) have revealed evidence of embryonic and fetal toxicity, including developmental toxicity, fetal anasarca, skeletal malformations, and increased incidence of stillbirth. Animal studies with lamivudine have failed to reveal evidence of teratogenicity; while early embryolethality was observed in rabbit studies (exposure levels similar to human levels), this effect was not seen in high-dose studies in rats. Placental transfer of each drug has been observed in humans. There are no controlled data in human pregnancy; however, based on observed outcomes with abacavir (more than 800 after first-trimester exposure and more than 1000 after second-/third-trimester exposure) and lamivudine (more than 1000 after first-trimester exposure and more than 1000 after second-/third-trimester exposure), the malformative risk is unlikely in humans. To monitor maternal-fetal outcomes of pregnant women exposed to antiretroviral therapy, an Antiretroviral Pregnancy Registry (APR) has been established. Healthcare providers are encouraged to prospectively register patients. For additional information: apregistry.com The APR has received prospective reports of over 2000 exposures to abacavir (over 900 exposed in the first trimester) and over 11,000 exposures to lamivudine (over 4300 exposed in the first trimester) resulting in live births; there was no difference between abacavir or lamivudine and overall birth defects compared with the background birth defect rate of 2.7% in the reference population. The prevalence of defects in the first trimester was 3% for abacavir and 3.1% for lamivudine. No increased risk of major birth defects observed for either drug compared to background rate. In 2 clinical trials, maternal, neonatal, and umbilical cord serum lamivudine levels were generally comparable. Amniotic fluid samples collected after natural rupture of membranes from a subset of patients confirmed placental transfer in humans. Amniotic fluid levels of lamivudine were usually 2 times greater than maternal serum levels, ranging from 1.2 to 2.5 mcg/mL (150 mg twice a day) and 2.1 to 5.2 mcg/mL (300 mg twice a day). AU TGA pregnancy category B3: Drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals have shown evidence of an increased occurrence of fetal damage, the significance of which is considered uncertain in humans. US FDA pregnancy category Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D, and X are being phased out.

This drug should be used during pregnancy only if the benefit outweighs the risk to the fetus. AU TGA pregnancy category: B3 US FDA pregnancy category: Not assigned. Risk summary: Malformative risk with use of this drug in pregnant women is unlikely. Comments: A pregnancy exposure registry is available.

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Abacavir / lamivudine Breastfeeding Warnings

Breastfeeding is not recommended during use of this drug; if replacement feeding is not an option, a different drug may be preferred. Excreted into human milk: Yes Comments: -The effects in the nursing infant are unknown. -The US CDC, American Academy of Pediatrics, and manufacturer advise HIV-infected women not to breastfeed to avoid postnatal transmission of HIV to a child who may not yet be infected. -Local guidelines should be consulted if replacement feeding is not an option.

ABACAVIR: Breast milk from 15 women and blood samples from 9 of their partially or exclusively breastfed infants were collected about 1 month postpartum; the mothers were using abacavir 300 mg twice a day for 53 to 182 days (with lamivudine and zidovudine). Breast milk was obtained right before a dose; whole breast milk abacavir levels averaged 0.057 mg/L (about 85% of maternal blood levels). Infant blood was obtained 11 to 17 hours after the last maternal dose and about 1 hour (range: 6 minutes to 35 hours) after the last breastfeeding; plasma abacavir levels were undetectable (less than 16 mcg/L) in 8 of 9 infants. LAMIVUDINE: Based on more than 200 mother/child pairs treated for HIV, serum lamivudine levels in breastfed infants of mothers treated for HIV are very low (less than 4% of maternal serum levels) and gradually decrease to undetectable levels by 24 weeks of age. Milk samples were obtained daily before breastfeeding. The milk lamivudine level averaged 1.2 mg/L (range: less than 0.5 to 6.1 mg/L) with 300 mg twice a day (n=10) and 0.9 mg/L (range: less than 0.5 to 8.2 mg/L) with 150 mg twice a day plus zidovudine (n=10). Milk samples from 20 women taking lamivudine 150 mg orally twice a day as part of combination antiretroviral therapy (cART) and serum levels from their infants were obtained at 2 or 5 months postpartum, about 4 hours (range: 1 to 8.5 hours) after the last dose. The drug level in breast milk averaged 1.8 mg/L and the infant serum lamivudine level averaged 28 mcg/L (range: less than 14 to 53 mcg/L). Breast milk from 15 women and blood samples from 24 of their partially or exclusively breastfed infants were collected about 1 month postpartum; the mothers were using lamivudine 150 mg twice a day for 53 to 182 days (with [abacavir or lopinavir-ritonavir] and zidovudine). Breast milk was obtained right before a dose; whole breast milk lamivudine levels averaged 0.14 mg/L (about 74% of maternal blood levels). Infant blood was obtained 11 to 18 hours after the last maternal dose and about 1 hour (range: 6 minutes to 35 hours) after the last breastfeeding. Plasma lamivudine levels were undetectable (less than 7 mcg/L) in all infant samples. Serum and breast milk from 58 mothers using lamivudine 150 mg twice a day (with nevirapine and zidovudine) and serum levels from their 58 infants were analyzed. Mothers started lamivudine at 34 to 36 weeks gestation and continued until 6 months postpartum; they were instructed to exclusively breastfeed for 5.5 months. Breast milk and serum samples were collected within 24 hours after delivery and at 2, 6, 14, and 24 weeks postpartum; breast milk was collected at various times after the prior dose. The breast milk lamivudine level averaged 1214 mcg/L (all visits). The infant dried blood spot lamivudine levels averaged 67 mcg/L at delivery, 32 mcg/L at week 2, 24 mcg/L at week 6, 20 mcg/L at week 14, and were not measurable (less than 16 mcg/L) at week 24 postpartum. A fully breastfed infant would receive 182 mcg/kg/day of lamivudine (estimated). Blood and milk samples were obtained from 40 women on postpartum prophylaxis (with lamivudine, nevirapine, and [zidovudine or stavudine]; doses not provided) once during the first 3 days postpartum and once at 7 days postpartum. Samples were collected after a dose at 5.3 hours (range: 0 to 99 hours) for the first sample and 6 hours (range: 4.3 to 20 hours) for the second sample. Breast milk lamivudine levels averaged 0.4 mg/L (n=20) for the first sample and 0.4 mg/L (n=30) for the second sample; these levels were 2.9 to 3.3 times the coinciding maternal serum levels. Mothers using lamivudine (dose not provided) as part of cART provided 47 breast milk and serum samples at 6, 12, and 24 weeks postpartum. The breast milk lamivudine levels at about 14 hours after the last dose averaged 510 (17 samples), 387 (17 samples), and 310 mcg/L (13 samples). Milk levels were about 2.6 times (interquartile range: 1.1 to 3.5 times) the maternal plasma levels; milk to plasma ratio was 2.96 in 49 patients in a related study (same authors). Infant serum levels measured about 14 hours after the last maternal dose averaged 13, 10, and 5 mcg/L at 6 (17 samples), 12 (17 samples), and 24 (13 samples) weeks of age, respectively, which was 6% of the maternal serum level. A total of 206 milk samples were obtained at birth, 1, 3, and/or 6 months postpartum from 66 mothers using lamivudine 150 mg twice a day as part of cART and 64 blood samples from their breastfed infants were analyzed at 1, 3, and/or 6 months postpartum; samples were collected at about 4.5 hours (range: 3.5 to 6 hours) after the prior maternal dose and about 30 minutes (range: 20 to 60 minutes) after nursing. Breast milk lamivudine level averaged 446 mcg/L (range: 269 to 683 mcg/L). Infant plasma lamivudine level averaged 18 mcg/L (range: 7 to 35 mcg/L), which averaged 2% (range: 0 to 4%) of the maternal serum level. In a continuation of this study, 65 breast milk samples (after the same dose at 1, 3, and 6 months postpartum) and 22 blood samples (from 17 breastfed infants [extent not provided] between 1 and 6 months) were collected for drug analysis; lamivudine levels averaged 684 mcg/L in breast milk and 29.2 mcg/L in infant blood. Unclear if some of the same patients from the first study were in the latter study. Mothers (n=30) starting lamivudine 150 mg orally twice a day (with zidovudine and lopinavir-ritonavir) at delivery provided plasma and breast milk samples at 6, 12, or 24 weeks postpartum (n=10 at each time). Maternal plasma and breast milk samples were collected about 14.9 hours after the prior evening dose, before the morning dose, and 2, 4, and 6 hours after the dose. Infant plasma samples were collected before the first maternal dose and at 2, 4, and 6 hours after the maternal dose. Breastfeeding was not restricted during the study. Detectable lamivudine levels (at least 10 mcg/L) were found in 107 of 121 breast milk samples and 107 of 115 infant plasma samples; breast milk level averaged 0.94 mg/L over the 6 hours and infant plasma level averaged 180 mcg/L.

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References for pregnancy information

  1. HHS Panel on Treatment of HIV-Infected Pregnant Women and Prevention of Perinatal Transmission "Recommendations for Use of Antiretroviral Drugs in Pregnant HIV-1-Infected Women for Maternal Health and Interventions to Reduce Perinatal HIV Transmission in the United States. Available from: URL: https://aidsinfo.nih.gov/contentfiles/lvguidelines/pe" ([2015 Aug 6]):
  2. "Product Information. Epzicom (abacavir-lamivudine)." GlaxoSmithKline, Research Triangle Park, NC.
  3. Cerner Multum, Inc. "Australian Product Information." O 0
  4. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

References for breastfeeding information

  1. United States National Library of Medicine "Toxnet. Toxicology Data Network. Available from: URL: http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT." ([cited 2013 -]):
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. "Product Information. Epzicom (abacavir-lamivudine)." GlaxoSmithKline, Research Triangle Park, NC.
  4. Cerner Multum, Inc. "Australian Product Information." O 0
  5. HHS Panel on Treatment of HIV-Infected Pregnant Women and Prevention of Perinatal Transmission "Recommendations for Use of Antiretroviral Drugs in Pregnant HIV-1-Infected Women for Maternal Health and Interventions to Reduce Perinatal HIV Transmission in the United States. Available from: URL: https://aidsinfo.nih.gov/contentfiles/lvguidelines/pe" ([2015 Aug 6]):
  6. Mirochnick M, Thomas T, Capparelli E, et al. "Antiretroviral Concentrations in Breast-feeding Infants of Mothers Receiving HAART." Antimicrob Agents Chemother (2008):
  7. "Infant feeding and transmission of human immunodeficiency virus in the United States." Pediatrics 131 (2013): 391-6

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