CDC recommends using an antibiotic as a ‘morning after pill’ for STDs

Doctors are being asked to consider prescribing a “morning after pill” after sex to combat the nationwide explosion of STD infections.

The CDC today released new guidelines recommending that the antibiotic doxycycline be prescribed within 72 hours of unprotected oral, vaginal, or anal sex with a new or returning partner.

Studies suggest the drug could prevent up to 70 percent of chlamydia and syphilis infections and up to 50 percent of gonorrhea cases.

It works by killing bacteria before they become so advanced that they cause symptoms and can be transmitted to others.

This comes amid an “STD epidemic” in the United States, with nearly 700,000 more Americans now catching chlamydia, gonorrhea or syphilis each year than before the Covid pandemic.

The new recommendations apply to gay and bisexual men as well as transgender women with a history of at least one STI.

But it may also be available to heterosexual men and women if they seek medical attention concerned that they may have been exposed to an STI.

The guidelines, released today, state that for these groups “providers should use clinical judgment and shared decision-making to inform use.”

Patients taking the course will also need to be tested for an STI at the start and three and six months after taking the medicine.

Doxycycline for STIs is prescribed as 200 milligrams (mg) taken twice daily for seven days.

Its purpose is only to reduce the risk of STIs, whereas the traditional morning-after pill, Plan B, must always be taken within 72 hours of unprotected sex to avoid unwanted pregnancy.

Officials said they recommend this course – called doxycycline post-exposure prophylaxis (Doxy-PEP) – for gay and bisexual men because this group is disproportionately affected by STIs.

This group has higher rates of syphilis than the general population and still accounts for more than half of all new HIV infections.

Officials said: “Doxy PEP represents the first new STI prevention tool in decades, at a time when innovation in the national fight against STIs is desperately needed.

“These guidelines will be updated as additional data becomes available.”

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Doxycycline has been used in the United States since its approval in 1967 and is taken in 60-day courses of two tablets per day.

It is available by prescription, with around 9 million drugs dispensed each year to treat everything from a chest and dental problem to a skin infection like rosacea and STIs.

It is not always prescribed for bacterial STIs, with the CDC recommending azithromycin for chlamydia, ceftriaxone for gonorrhea, and penicillin for syphilis.

Infections are already becoming resistant to these drugs, with concerns raised last year over two cases of super-gonorrhea – or antibiotic-resistant gonorrhea – detected in Boston, Massachusetts.

But there are concerns that prescribing doxycycline to treat infections could have the same effect.

Studies suggest that about five percent of chlamydia infections may already be resistant to doxycycline, with resistance likely already present in gonorrhea and syphilis.

Studies suggest there was no marked increase in resistance when doxy-PEP was used, but there was a slight increase in resistance levels among Staph bacteria – which can cause infections of the throat – increasing from 5 to 13 percent.

Doxycycline is also associated with side effects, including vomiting or diarrhea, headache, and feeling nauseous.

This comes amid an explosion of STIs in the United States, where every state sees cases of syphilis and gonorrhea increase between 2017 and 2022, according to the latest available data.

Only chlamydia, the most common STI in the United States, appears to trigger fewer infections – but there are concerns that this is because fewer tests have been done.

Scientists fear that the rise in STIs is due to riskier sexual behavior and a reduction in condom use.

Experts are particularly concerned about rising rates of syphilis because the disease can cause birth defects in developing fetuses.

The latest guidelines were based on three studies of gay and bisexual men who received 200 milligrams (mg) of doxycycline within 72 hours of sexual intercourse.

This included a 2022 trial in San Francisco and Seattle, where 501 gay and bisexual men and transgender women who had never used a condom during sex were given doxycycline for up to 72 hours after sex.

And a 2022 trial carried out in France involving 332 people who received doxycycline within 72 hours of sex, with a history of sex without a condom.

Participants were followed for 96 weeks, with results showing a 50 percent reduction in the risk of gonorrhea infection and up to a 90 percent reduction in the risk of chlamydia or gonorrhea infection.

The recommendation follows a public consultation on the measure, which was first revealed in April last year.