The high drug concentrations raised the possibility of some risks, as well as benefits, however. Such levels may be high enough to cause adverse effects associated with the drugs, such as rash, neutropenia, and anemia, and to lead to the emergence of drug-resistant virus.
For the second study, the researchers examined the ability of combination antiretroviral therapy to reduce HIV-1 RNA and DNA levels in breast milk. They measured these levels in two groups: 26 women who received nevirapine, lamivudine, and zidovudine beginning during pregnancy or postpartum, and 25 women from an earlier time period with comparable HIV disease, who did not receive antiretroviral therapy because it was unavailable to them at the time they were breastfeeding.
The results indicated that antiretroviral therapy suppresses HIV RNA in breast milk and may therefore reduce mother-to-child transmission of HIV during breastfeeding. Eighty-eight percent of the women receiving antiretroviral therapy had fewer than 50 copies/ml of HIV-1 RNA in their breast milk, compared with 36 percent of the women not taking therapy. This represents a statistically significant difference.
However, there was no such difference for HIV-1 DNA, which some studies suggest also contributes to mother-to-child transmission. One possible explanation for this lack of association between antiretroviral therapy and HIV DNA levels, the investigators hypothesized, may be the short duration of treatment in the study (a median of 98 days). Combination antiretroviral therapy may reduce HIV DNA in breast milk more slowly than HIV RNA, thus raising the risk that, when treatment duration is short, HIV DNA-associated transmission may occur despite the
Source:Infectious Diseases Society of America