Two drugs commonly used to prevent mother-to-child transmissions of HIV have considerable drawbacks, according to recent studies. Data presented at the 11th Conference on Retroviruses and Opportunistic Infections showed that single doses of the nonnucleoside reverse transcriptase inhibitor Viramune given to HIV-positive mothers during childbirth can lead to the development of resistance to the drug in the women and their babies.
A study of treatment-naive HIV-positive pregnant women in South Africa shows that 38.8% of the women and 42.4% of the infants developed resistance to Viramune after the single dose. The drug's 'effect on subsequent pregnancies and choice of highly active antiretroviral therapy regimen remains to be explored,' the researchers report.
A study by researchers at the University of Nevada shows that the nucleoside reverse transcriptase inhibitor AZT can have toxic effects on the placenta of HIV-positive pregnant women. AZT decreased cellular proliferation rates, was toxic to mitochondria, altered metabolizing enzymes, and caused cell death in the placenta, among other toxic side effects observed, according to the study, which was published in the journal Toxicology and Applied Pharmacology. The researchers, who noted that AZT is the drug of choice to prevent vertical HIV transmissions, conclude that the toxic effects of the medication on placental cells may affect the integrity of the maternal-fetal barrier.