A 24-year-old woman attends a family planning clinic with complaints of mucopurulent cervical discharge and lower abdominal pain for 2 weeks. Cervical swab nucleic acid amplification test (NAAT) is positive for *Chlamydia trachomatis* but negative for *Neisseria gonorrhoeae*. She is not pregnant and has no drug allergies. What is the most appropriate next step in management?

Explanation

## Chlamydial Cervicitis Management ### Clinical Context **Key Point:** NAAT-confirmed *Chlamydia trachomatis* cervicitis without concurrent gonorrhea requires treatment with a first-line regimen. The choice of agent depends on pregnancy status, drug allergies, and local resistance patterns. ### Correct Answer: Doxycycline Monotherapy **High-Yield:** For non-pregnant women with confirmed chlamydial cervicitis (and negative gonorrhea NAAT), doxycycline 100 mg orally twice daily for 7 days is the preferred first-line agent [cite:CDC STI Treatment Guidelines 2021]. This regimen: 1. Achieves >95% cure rate for uncomplicated chlamydia 2. Is cost-effective and widely available 3. Has excellent tissue penetration to the genital tract 4. Does not require parenteral administration 5. Avoids unnecessary cephalosporin use (which should be reserved for gonorrhea) **Clinical Pearl:** In the absence of gonorrhea (confirmed by negative NAAT), ceftriaxone is not indicated. Adding ceftriaxone would constitute overtreatment and unnecessarily increase antibiotic pressure and cost. ### Treatment Algorithm for Chlamydia ```mermaid flowchart TD A[Chlamydia NAAT positive]:::outcome --> B{Pregnant?}:::decision B -->|Yes| C[Azithromycin 1 g PO single dose OR Amoxicillin 500 mg TDS × 7 days]:::action B -->|No| D{Gonorrhea co-infection?}:::decision D -->|Yes| E[Ceftriaxone 250 mg IM + Doxycycline 100 mg BD × 7 days]:::action D -->|No| F[Doxycycline 100 mg BD × 7 days]:::action C --> G[Test of cure at 3-4 weeks]:::outcome E --> G F --> G ``` ### Comparison of Chlamydia Treatment Regimens | Scenario | First-line | Cure Rate | Notes | |----------|-----------|-----------|-------| | Non-pregnant, no gonorrhea | Doxycycline 100 mg BD × 7 d | >95% | Preferred; cost-effective | | Pregnant | Azithromycin 1 g single dose | 90–95% | Safe in pregnancy; avoid doxycycline (teratogenic) | | Pregnant (alternative) | Amoxicillin 500 mg TDS × 7 d | 90–95% | If azithromycin intolerance | | Non-pregnant + gonorrhea | Ceftriaxone 250 mg IM + Doxycycline | >95% | Dual therapy for both pathogens | | Allergy to tetracyclines | Azithromycin 1 g single dose | 90–95% | Acceptable alternative | **Mnemonic:** **DOX-7** = **DOX**ycycline for 7 days in non-pregnant chlamydia