What is the best prophylactic antibiotic for post-coital (after sexual intercourse) exposure?

From the Guidelines

The best prophylactic antibiotic for post-coital exposure is ceftriaxone 125 mg IM in a single dose, or ciprofloxacin 500 mg orally in a single dose, plus azithromycin 1 g orally in a single dose if chlamydial infection is not ruled out. This recommendation is based on the most recent and highest quality study available, which suggests that these regimens are effective against uncomplicated gonococcal infections and chlamydia 1.

Key Considerations

• The choice of antibiotic should be guided by the potential for chlamydial coinfection, which is more common at genital sites.
• Patients who have symptoms that persist after treatment should be evaluated by culture for N. gonorrhoeae, and any gonococci isolated should be tested for antimicrobial susceptibility.
• Regular STI testing remains essential even when using prophylactic antibiotics, as no method provides 100% protection.

Important Details

• Ceftriaxone 125 mg IM in a single dose is a recommended regimen for uncomplicated gonococcal infections.
• Ciprofloxacin 500 mg orally in a single dose is an alternative option, but its effectiveness may be reduced in areas with high resistance rates.
• Azithromycin 1 g orally in a single dose is recommended if chlamydial infection is not ruled out, as it is effective against chlamydia and can help prevent coinfection.
• Patients should be instructed to refer their sex partners for evaluation and treatment, and all sex partners of patients who have N. gonorrhoeae infection should be evaluated and treated for N. gonorrhoeae and C. trachomatis infections if their last sexual contact with the patient was within the recommended timeframe.

From the FDA Drug Label

Adults: The usual dose of oral doxycycline is 200 mg on the first day of treatment (administered 100 mg every 12 hours) followed by a maintenance dose of 100 mg/day Uncomplicated gonococcal infections in adults (except anorectal infections in men):100 mg, by mouth, twice a day for 7 days. As an alternate single visit dose, administer 300 mg stat followed in one hour by a second 300 mg dose. Uncomplicated urethral, endocervical, or rectal infection in adults caused by Chlamydia trachomatis: 100 mg, by mouth, twice a day for 7 days.

The best prophylactic antibiotic for post-coital exposure is not explicitly stated in the provided drug label. However, based on the available information, doxycycline can be considered as a potential option for the treatment of certain sexually transmitted infections, such as gonococcal and chlamydial infections.

• The recommended dose for uncomplicated gonococcal infections is 100 mg, by mouth, twice a day for 7 days, or a single visit dose of 300 mg stat followed by a second 300 mg dose in one hour.
• The recommended dose for uncomplicated chlamydial infections is 100 mg, by mouth, twice a day for 7 days. It is essential to note that the provided drug label does not directly address post-coital prophylaxis, and the decision to use doxycycline for this purpose should be made with caution and under the guidance of a healthcare professional 2.

From the Research

Prophylactic Antibiotics for Post-Coital Exposure

• The use of prophylactic antibiotics after sexual intercourse is a topic of interest, particularly in preventing sexually transmitted infections (STIs) such as gonorrhea and chlamydia 3, 4, 5, 6, 7.
• Azithromycin has been studied as a potential prophylactic antibiotic, with evidence suggesting its effectiveness in treating gonorrhea and chlamydia 3, 4, 6.
• A study from 1994 found that a single dose of azithromycin was as effective as a 7-day regimen of doxycycline in treating chlamydia and gonorrhea 3.
• Another study from 2013 compared the effectiveness of ceftriaxone plus azithromycin versus ceftriaxone plus doxycycline in treating gonorrhea, and found that azithromycin may be preferable as the second agent due to its potential to reduce retreatment rates 4.
• The 2021 CDC STI Treatment Guidelines recommend 500mg ceftriaxone intramuscularly once for the treatment of uncomplicated gonorrhea, and suggest cotreatment with doxycycline 100mg twice daily for 7 days if coinfection with chlamydia has not been excluded 5.
• Azithromycin has been shown to be well-tolerated and effective in treating STIs, including gonorrhea and chlamydia 3, 6.
• The use of antibiotic prophylaxis post-sexual assault has been studied, with evidence suggesting that it is acceptable to women and may be beneficial in preventing STIs 7.

Considerations for Prophylactic Antibiotic Use

• The choice of prophylactic antibiotic should be based on the specific STIs being targeted, as well as the potential for antibiotic resistance 4, 5.
• The use of azithromycin as a prophylactic antibiotic may be limited by its potential for resistance, as well as its side effects and interactions with other medications 3, 4, 6.
• Further research is needed to determine the optimal prophylactic antibiotic regimen for post-coital exposure, as well as the cost-benefit analysis of such a regimen 7.