Tenofovir, when administered as a gel, is safe for intravaginal use as a microbicide to prevent HIV transmission, according to a study published in the Feb. 28 on-line edition of the journal AIDS, Reuters Health reports (Reuters Health, 2/22). Microbicides include a range of products -- such as gels, films, sponges and other products -- that could help prevent the sexual transmission of HIV and other sexually transmitted diseases (Kaiser Daily HIV/AIDS Report, 1/26). Kenneth Mayer, director of the Brown University AIDS Program, and colleagues looked at 84 women ages 18 to 45. The participants, 60 of whom were HIV-negative and 24 of whom were HIV-positive, were given tenofovir to use intervaginally for 14 consecutive days, according to a release from the Rhode Island-based Lifespan Health System (Lifespan release, 2/10). Most participants reported at least one mild adverse event, but the study does not find an association between adverse events and gel concentration, sexual activity or HIV status, Reuters Health reports. About 94% of the women said they would definitely or probably use the tenofovir gel to prevent HIV transmission if it were available (Reuters Health, 2/22). Researchers did not detect any new resistance mutations in the 24 HIV-positive women after 14 days of use (Mayer et al., AIDS, 2/28). Mayer called use of tenofovir as a microbicide "an innovative approach that shows great promise," adding, "The results of this study may change the way the research community looks at developing safe and effective microbicides" (Lifespan release, 2/10). Researchers said further studies are underway in New York and India to examine tenofovir's efficacy as a microbicide (Reuters Health, 2/22).