The use of Truvada (tenofovir/emtricitabine) as pre-exposure prophylaxis (PrEP) is on the rise in the United States, in particular among men, aidsmap reports. Researchers from academia as well as Gilead Sciences, which manufactures Truvada but does not actively promote it as an HIV prevention tool, conducted an analysis of data from 55 percent of American pharmacies from January 2012 through March 2014. This was an update of previous national estimates of the number of people using PrEP. The researchers presented their findings at the HIV Drug Therapy 2014 conference in Glasgow, Scotland.

It is tricky to determine how many people are taking PrEP because there is no specific prescribing code for that particular indication for Truvada. So to make a best guess, researchers must work backward, looking at Truvada prescriptions and then eliminating those prescribed for HIV treatment, for post-exposure prophylaxis (PEP) or for hepatitis B virus treatment.

The remaining data still paints a highly incomplete picture of PrEP usage in the United States. For starters, the information was culled from only the limited proportion of pharmacies. Also, it does not account for prescriptions through Medicaid or for people who are on PrEP as part of a clinical trial or demonstration project. The analysis only runs through March 2014, which precedes the Centers for Disease Control and Prevention’s revised guidelines on PrEP, issued May 15, which garnered a great deal of press and spurred the activist community to push for greater Truvada use among gay men in particular. The summer also saw the release of results from the iPrEx open-label (OLE) phase, further influencing interest in PrEP.

The analysis indicated that, among the pharmacies studied, 1,057 new prescriptions for PrEP were filled during the first nine months of 2013. An additional 880 people began PrEP from October 2013 through March 2014. All told, 3,253 people have filled PrEP prescriptions at these pharmacies since January 2012.

The proportion of women taking PrEP has apparently declined since the last analysis of PrEP use was released. During the first half of 2012, 53.9 percent of the PrEP prescriptions in these pharmacies were among women, compared with 26.7 percent from October 2013 through March 2014. In March 2013, 44.5 percent of new PrEP prescriptions were among women, compared with 22.9 percent a year later.

The average age of PrEP users detected in this analysis has remained steady throughout the periods studied, at 38 years old. However, while 13.9 percent of people using PrEP were under 25 in early 2012, this figure dropped to 10.8 percent in the most recent period studied.

Sixty-eight percent of PrEP prescriptions were written by clinicians in five different specialties: internal medicine (19 percent), family practice (18 percent), infectious diseases (11 percent), nurse practitioners (10 percent) and physician assistants (10 percent).

To read the aidsmap story, click here.

To read the data from the conference poster, click here.