General practitioners can intervene to treat and prevent STDs

VANCOUVER, British Columbia – Primary care physicians should familiarize themselves with doxycycline post-exposure prophylaxis (doxy PEP) as a prescription for patients who frequently have unprotected sex (including oral, anal and vaginal) with multiple partners, according to a presentation at the Family Medicine Forum (FMF) 2024. Doxy PEP reduces the risk of bacterial sexually transmitted infections (STDs).

Many GPs may not be aware of doxy PEP as a means of preventing STDs. “Doxy PEP is an incredible tool that can be used within 72 hours of unprotected sex to reduce bacterial STD risk,” says James Owen, MD, assistant professor of family and community medicine at the University of Toronto, Toronto, Ontario, Canada.

The U.S. Centers for Disease Control and Prevention points to data from three randomized, controlled trials showing doxy PEP’s ability to reduce syphilis and chlamydia infections by more than 70% and reduce gonococcal infections by about 50%, noted Jordan Goodridge , MD, op. assistant professor of family and community medicine at the University of Toronto.

Optimizing Doxy PEP

Doxy PEP (200 mg) is most effective when administered in the first 24 hours after unprotected sex, Goodridge explains. It is recommended that patients repeat the 200 mg dose if they return to sexual activity within 24 hours.

To ensure optimal absorption of doxy PEP, the drug should not be taken with antacids or multivitamins, Goodridge said. Antacids “can bind to doxycycline and prevent it from being absorbed,” he said.

A major concern about doxy PEP is the development of antimicrobial resistance, Goodridge noted. “We don’t have long-term studies to give us an idea of ​​what this risk is and to quantify it. The studies we have are relatively short, generally less than a year, and have not suggested that there was a high risk (for antimicrobial resistance).”

In addition, doxycycline is teratogenic and its use is contraindicated during pregnancy, Goodridge said. If a pregnant patient is being treated for syphilis, penicillin is the treatment of choice. For pregnant patients with a penicillin allergy, the Public Health Agency of Canada guidelines call for penicillin desensitization followed by penicillin.

Rates of syphilis have risen among Canadian women of childbearing age, increasing the risk of congenital syphilis, Goodridge noted.

Benefits of the HPV vaccine

The 9-valent HPV vaccine is recommended in Canada for patients aged 9 to 26 years, but those aged 27 or older who are at ongoing risk of exposure to HPV can receive the 9-valent HPV vaccine after consulting with their healthcare providers , Owen noted.

High-risk patients may benefit from the vaccine even though they have likely been exposed to HPV, he added. “If someone has multiple sexual partners, they have likely been exposed to HPV at some point,” says Owen. “You could still reduce a patient’s risk of being exposed to certain oncogenic strains (of HPV). Certainly, within our practices we often give it (i.e. the HPV vaccine) to higher risk individuals, including men who have sex with men.

HIV prevention

“Condoms are still a mainstay of HIV and STD prevention, but condom use is declining,” says Owen.

In a national survey commissioned by the Toronto-based organization LetsStopAIDS, which included more than 1,100 Canadians aged 18 to 24, 24% of respondents said they “always” use condoms. In contrast, in 2020, more than half (53%) of respondents reported continuous use of condoms.

Updated Canadian guidelines on the use of HIV pre-exposure prophylaxis (PrEP) are expected to be released in 2025 and will answer questions about how often individuals taking HIV PrEP should be tested to ensure a negative HIV result. The guidelines will also provide guidance on whether to map HIV serology or HIV viral load, Owen said. Patients in Canada using HIV PrEP are now typically screened for HIV every three months.

A new tool for HIV PrEP that has become available to Canadian physicians is the injectable drug cabotegravir, which is dosed every two months.

Owen and Goodridge reported that they had no relevant financial relationships.