What are the treatment options for syphilis and chlamydia?

Treatment for Syphilis and Chlamydia

Syphilis Treatment

Primary and Secondary Syphilis (Early Syphilis)

Benzathine penicillin G 2.4 million units intramuscularly as a single dose is the definitive treatment for primary and secondary syphilis. 1, 2

• This regimen has over 40 years of proven clinical effectiveness in achieving local cure, healing lesions, preventing sexual transmission, and preventing late sequelae 3
• The same single-dose regimen applies regardless of HIV status 3, 1

Latent Syphilis

For early latent syphilis (acquired within the past year), give benzathine penicillin G 2.4 million units IM as a single dose. 1, 4

For late latent syphilis or syphilis of unknown duration, give benzathine penicillin G 2.4 million units IM weekly for 3 consecutive weeks (total 7.2 million units). 1, 4

• Early latent syphilis is defined by documented seroconversion, unequivocal symptoms of primary or secondary syphilis within the past year, or a sex partner with documented early syphilis 4
• All other cases should be treated as late latent syphilis 3, 4

Alternative Regimens for Penicillin Allergy (Non-Pregnant Patients)

Doxycycline 100 mg orally twice daily for 14 days is the preferred alternative for penicillin-allergic patients with primary, secondary, or early latent syphilis. 1, 5, 6

• For late latent syphilis in penicillin-allergic patients, extend doxycycline to 100 mg orally twice daily for 28 days 4, 5, 6
• Doxycycline is preferred over tetracycline due to better compliance with twice-daily versus four-times-daily dosing 1, 5
• Tetracycline 500 mg orally four times daily for 14 days (early) or 28 days (late latent) is an acceptable alternative but less practical 1, 4
• Ceftriaxone 1 g daily (IM or IV) for 8-10 days may be considered, though optimal dosing is not well established 1

Critical caveat: Pregnant patients with penicillin allergy must be desensitized and treated with penicillin—there are no acceptable alternatives in pregnancy. 4, 5

Special Considerations

HIV Co-infection

• HIV-infected patients receive the same penicillin regimens as HIV-negative patients 3, 1
• However, closer follow-up is required: every 3 months instead of every 6 months 1, 5
• For late latent syphilis in HIV-infected patients, perform CSF examination before treatment to exclude neurosyphilis 3, 4

Pre-Treatment Evaluation for Latent Syphilis

• Perform lumbar puncture before treatment if any of the following are present: neurologic or ophthalmic signs/symptoms, evidence of active tertiary syphilis, treatment failure, HIV infection with late latent syphilis, or nontreponemal titer ≥1:32 (unless duration <1 year is documented) 4
• If CSF shows neurosyphilis, treat with aqueous crystalline penicillin G 18-24 million units IV daily for 10-14 days instead 4

Follow-Up Protocol

• Perform clinical and serologic evaluation at 6 and 12 months after treatment for early syphilis 3, 1
• For latent syphilis, repeat quantitative nontreponemal tests at 6,12, and 24 months 4, 5
• Treatment failure is defined by: persistent or recurring signs/symptoms, sustained fourfold increase in nontreponemal titers, or failure of initially high titers to decline fourfold within 6-12 months 3, 1, 4
• HIV-infected patients require more frequent monitoring at 3-month intervals 1, 5

Common Pitfalls

• Jarisch-Herxheimer reaction (fever, headache, myalgia) may occur within 24 hours after treatment, especially in early syphilis—this is expected and does not indicate treatment failure 1
• Macrolide resistance in T. pallidum is widespread in the United States, making azithromycin unsuitable despite some historical evidence of efficacy 1
• Serologic tests may decline more slowly in patients with previous syphilis infections 3, 1
• Benzathine penicillin G shortages have occurred; when unavailable, doxycycline can be initiated while actively searching for penicillin 7

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Chlamydia Treatment

Note: The provided evidence does not contain specific guidelines or recommendations for chlamydia treatment. Based on standard medical knowledge and the brief mention in the evidence:

Standard Treatment (General Medical Knowledge)

Doxycycline 100 mg orally twice daily for 7 days is the first-line treatment for uncomplicated chlamydial infections. 6

• The FDA label for doxycycline specifies this regimen for uncomplicated urethral, endocervical, or rectal infection caused by Chlamydia trachomatis 6
• Alternative: Azithromycin 1 g orally as a single dose (though doxycycline is preferred due to higher efficacy)

Special Populations

• Pregnant patients: Azithromycin 1 g orally as a single dose is preferred (doxycycline is contraindicated in pregnancy)
• Nongonococcal urethritis (NGU) caused by C. trachomatis: Doxycycline 100 mg orally twice daily for 7 days 6

Follow-Up

• Test of cure is recommended 3-4 weeks after treatment completion in pregnant patients
• Retest all patients 3 months after treatment due to high reinfection rates
• Treat sexual partners from the past 60 days