Women Need More Truvada Than Men To Prevent HIV

Women need daily doses of the HIV prevention drug Truvada, while men need it twice a week, according to research done by a group of UNC researchers.

“Our data highlight the fact that one dose does not fit all,” said senior author Angela Kashuba. “In determining how best to use drugs to protect people from HIV, we need to understand where in their body they are at risk for being infected, along with the concentration of drug that is needed to protect that site from infection.”

Truvada was approved in 2012 to help prevent the spread of HIV, and it is the only drug approved by the FDA that has been shown to reduce HIV infection rates.

Previous studies have shown that Truvada was more effective in men than women when given the same dose, but this study is the first to offer an explanation as to why.

The team shows that vaginal, cervical and rectal tissue all respond differently to Truvada. Twice as much of the drug is needed to prevent HIV infection in vaginal and cervical tissue than rectal tissue because fewer components of Truvada make it into those two tissue types.

“The more DNA material there is available for HIV to work with, the more medicine is needed to block the process,” said lead author of the study Mackenzie Cottrell. “In essence, we calculated the most effective drug-to-DNA ratio for each tissue type.”

The team used human cells in a test tube to measure how much DNA material was in the cells and how much Truvada was needed to prevent HIV infection in these cells.

“We would like to remind people who are taking pre-exposure prophylaxis that Truvada should be taken every day to reduce the risk of acquiring HIV infection,” Kashuba said. “Patients should not change their medication regimen without first consulting their physicians.”