What are the recommended antibiotics for Chlamydia (Chlamydia trachomatis), Gonorrhea (Neisseria gonorrhoeae), and Syphilis (Treponema pallidum)?

From the Guidelines

For the treatment of chlamydia, gonorrhea, and syphilis, the most effective antibiotic regimens are azithromycin 1.0-1.5g as a single dose for chlamydia, ceftriaxone 1g as a single intramuscular or intravenous dose for gonorrhea, and benzathine penicillin G 2.4 million units as a single intramuscular injection for syphilis, as recommended by the European Association of Urology guidelines 1.

Key Considerations

• For chlamydia, alternative treatment options include doxycycline 100mg twice daily for 7 days, levofloxacin 500mg daily for 7 days, or ofloxacin 200mg twice daily for 7 days 1.
• For gonorrhea, alternative treatment options include cefixime 400mg as a single dose plus azithromycin 1g as a single dose, or gentamicin 240mg as a single intramuscular dose plus azithromycin 2g as a single dose 1.
• For syphilis, doxycycline 100mg twice daily for 14 days can be used as an alternative treatment for penicillin-allergic patients 1.

Treatment Duration and Completion

• It is essential to complete the full course of antibiotics even if symptoms improve, and to abstain from sexual activity until treatment is complete and partners are treated.
• Follow-up testing is recommended to ensure the infection has cleared, particularly for gonorrhea due to increasing antibiotic resistance.

Mechanism of Action

• These specific antibiotics are effective because they target the bacterial mechanisms of these infections - azithromycin inhibits protein synthesis, ceftriaxone disrupts cell wall formation, and penicillin interferes with bacterial cell wall synthesis.

Special Considerations

• In cases of cephalosporin allergy, alternative treatment options for gonorrhea include gentamicin 240mg as a single intramuscular dose plus azithromycin 2g as a single dose, or gemifloxacin 320mg as a single dose plus azithromycin 2g as a single dose 1.
• For persistent non-gonococcal urethritis, azithromycin 500mg as a single dose on day 1, followed by 250mg daily for 4 days, can be used as an alternative treatment option 1.

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. Uncomplicated urethral, endocervical, or rectal infection in adults caused by Chlamydia trachomatis: 100 mg, by mouth, twice a day for 7 days. Syphilis–early: Patients who are allergic to penicillin should be treated with doxycycline 100 mg, by mouth, twice a day for 2 weeks Infections caused by Chlamydia trachomatis such as uncomplicated urethral, endocervical or rectal infections, inclusion conjunctivitis, trachoma, and lymphogranuloma venereum. Syphilis and yaws caused by Treponema pallidum and pertenue, respectively, Infections caused by Neisseria gonorrhoeae

Antibiotics for Chlamydia, Gonorrhea, and Syphilis:

• Doxycycline is recommended for the treatment of:
  • Uncomplicated gonococcal infections: 100 mg, twice a day for 7 days 2
  • Uncomplicated Chlamydia trachomatis infections: 100 mg, twice a day for 7 days 2
  • Early syphilis: 100 mg, twice a day for 2 weeks in patients allergic to penicillin 2
• Tetracycline is also effective against:
  • Chlamydia trachomatis infections 3
  • Neisseria gonorrhoeae infections 3
  • Syphilis caused by Treponema pallidum 3

From the Research

Antibiotics for Chlamydia

• Azithromycin is a commonly used antibiotic for the treatment of chlamydia, with a single 1-g dose being as effective as a standard seven-day course of doxycycline 4.
• However, recent studies have raised concerns about the efficacy of azithromycin for the treatment of rectal chlamydia, with one study finding that a 7-day course of doxycycline was superior to single-dose azithromycin 5.
• Another study found that the efficacy of azithromycin was 97%, and the efficacy of doxycycline was 100% for the treatment of urogenital chlamydia infection 6.

Antibiotics for Gonorrhea

• There is no direct evidence in the provided studies for the treatment of gonorrhea with antibiotics.
• However, it is mentioned that a single-dose regimen of 250 mg of intramuscular ceftriaxone is effective for the treatment of chancroid, which is a different sexually transmitted disease 7.

Antibiotics for Syphilis

• Parenteral penicillin continues to be the drug of choice for the treatment of all stages of syphilis 7.
• There is no further information provided in the studies about the treatment of syphilis with other antibiotics.

Comparison of Antibiotics

• Azithromycin and doxycycline are two commonly used antibiotics for the treatment of chlamydia, with doxycycline being superior for the treatment of rectal chlamydia 5.
• The choice of antibiotic may depend on the specific type of infection, as well as the patient's medical history and other factors 8, 6.