Guides concerning tenofovir exposure via breastfeeding: A comparison of drug dosages by developmental stage

Int J Infect Dis. 2019 Oct:87:8-12. doi: 10.1016/j.ijid.2019.07.023. Epub 2019 Jul 26.

Abstract

Tenofovir disoproxil fumarate (TDF) is a prodrug of tenofovir, and after being administered orally, it converts to tenofovir in the blood. With the increasing use of TDF in women for treatment and prevention of mother-to-child transmission (MTCT) of both human immunodeficiency virus (HIV) and hepatitis B virus (HBV), or the pre-exposure prophylaxis (PrEP) for HIV, many nursing mothers have to understand the risk of exposure to tenofovir via breastmilk and make the decision about breastfeeding while on TDF treatment. Despite the safety record of TDF in pregnancy, some guidelines recommend against its use during breastfeeding. In this paper, we compared the dosage levels of tenofovir exposure in fetuses, breastfed infants, and children receiving tenofovir treatment. We found that breastfed infants were exposed to only 0.5%-16% of the tenofovir dosage that fetuses experienced via placental transfer, and 0.01-0.04% of the recommended weight-adjusted therapeutic dose. The assessment of toxicity risk from the dose perspective is an important and natural way of addressing safety concerns about exposure to tenofovir via breastfeeding. Based on the safety data from fetuses and children with tenofovir exposure, and the comparatively negligible exposure dosage from breastfeeding, our study supports mothers on TDF treatment should be encouraged to breastfeed.

Keywords: Antiviral therapy; Breastfeeding; Hepatitis B virus; Human Immunodeficiency virus; Tenofovir disoproxil fumarate.

Publication types

  • Comparative Study
  • Review

MeSH terms

  • Animals
  • Anti-HIV Agents / analysis
  • Anti-HIV Agents / therapeutic use*
  • Antiviral Agents / analysis
  • Antiviral Agents / therapeutic use
  • Female
  • HIV Infections / drug therapy
  • HIV Infections / prevention & control*
  • Hepatitis B / prevention & control
  • Hepatitis B / virology
  • Humans
  • Infectious Disease Transmission, Vertical / prevention & control*
  • Male
  • Milk, Human / chemistry
  • Pregnancy
  • Pregnancy Complications, Infectious / prevention & control*
  • Pregnancy Complications, Infectious / virology
  • Tenofovir / analysis
  • Tenofovir / therapeutic use*

Substances

  • Anti-HIV Agents
  • Antiviral Agents
  • Tenofovir