CDC recommends using antibiotic as a ‘morning after pill’ for STDs – to halt epidemic of syphilis, chlamydia and gonorrhea

Doctors are being told to consider prescribing a ‘morning after pill’ after sex to tackle the nationwide explosion of STD infections.

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

Studies suggest the drug can 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 have progressed to the point where they cause symptoms and can be transmitted to others.

It comes amid an “STD epidemic” in the US, with nearly 700,000 more Americans now contracting chlamydia, gonorrhea or syphilis each year compared to before the Covid pandemic.

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

But it may also be available to heterosexual men and women if they go to the doctor because they fear they have been exposed to an STD.

The guideline published today states this for these groups “providers should use their clinical judgment and shared decision-making to inform use.”

Patients receiving the course should also be tested for an STD when they start and three and six months after taking the drug.

Doxycycline for STDs is prescribed in a dose of 200 milligrams (mg), which should be taken twice a day for seven days.

It is only intended to lower STD risk, while the traditional morning-after pill, Plan B, must still be taken within 72 hours of unprotected sex to prevent an unwanted pregnancy.

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

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 STD prevention tool in decades, at a time when innovation in the country’s fight against STDs is desperately needed.

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

Doxycycline has been used in the US since its approval in 1967 and is taken in 60-day regimens of two pills per day.

It is available by prescription, and about 9 million are written each year to treat everything from breast and dental problems to skin infections such as rosacea and STDs.

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

The infections are already becoming resistant to these drugs, after concerns were raised last year about two cases of super gonorrhea – or gonorrhea that is resistant to antibiotics – discovered in Boston, Massachusetts.

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

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

Studies suggest there was no apparent increase in resistance when doxy-PEP was used, but there was an increase in resistance levels among staphylococcus bacteria – which can cause throat infections – from five to 13 percent.

Doxycycline is also associated with side effects such as vomiting or diarrhea, headaches, and a feeling of nausea.

It comes amid an explosion of STDs in the US, with every state seeing a spike in cases of syphilis and gonorrhea between 2017 and 2022, the most recent data available shows.

Only chlamydia, the most common STD in the US, appeared to cause fewer infections – but there are fears this is because fewer tests were being done.

Scientists fear that the increase in the number of STDs is caused by riskier sexual behavior and a decrease in condom use.

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

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

This included a 2022 trial conducted in San Francisco and Seattle in which 501 gay and bisexual men and transgender women who had not previously used a condom during sex were given doxycycline for up to 72 hours after sex.

And a 2022 trial conducted in France involved 332 people given doxycycline within 72 hours of sex, with a history of condomless sex.

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

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