What is the recommended treatment for a female with brown vaginal discharge after unprotected sex?

Brown Vaginal Discharge After Unprotected Sex

For a woman presenting with brown vaginal discharge after unprotected sex, empiric treatment should cover the most common sexually transmitted infections (STIs) and bacterial vaginosis (BV), particularly if follow-up is uncertain or if she meets high-risk criteria (age <25 years, new or multiple partners). 1

Initial Clinical Assessment

Key History and Physical Findings to Evaluate

• Discharge characteristics: Brown discharge may represent old blood mixed with vaginal secretions, which can occur with cervicitis, BV, or trichomoniasis 1
• Vaginal pH testing: pH >4.5 suggests BV or trichomoniasis rather than candidiasis 1
• Whiff test: Fishy odor with KOH application indicates BV or trichomoniasis 1
• Microscopy findings: Look for clue cells (BV), motile trichomonads, or inflammatory cells suggesting cervicitis 1
• Risk assessment: Unprotected sex is a key risk factor for STIs including chlamydia, gonorrhea, and trichomoniasis 1

Recommended Treatment Approach

Empiric Treatment Regimen (Preferred When Follow-up Uncertain)

The CDC recommends empiric coverage for the most common post-sexual exposure infections when follow-up cannot be ensured: 1

• Ceftriaxone 125 mg IM single dose (covers gonorrhea) 1
• Azithromycin 1 g orally single dose OR Doxycycline 100 mg orally twice daily for 7 days (covers chlamydia) 1
• Metronidazole 2 g orally single dose (covers trichomoniasis and BV) 1, 2

Alternative Approach If Follow-up Is Assured

If the patient can reliably return for results and you can perform diagnostic testing:

• Obtain nucleic acid amplification testing (NAAT) for chlamydia and gonorrhea 1, 3
• Perform wet mount microscopy for trichomonads and clue cells 1
• Measure vaginal pH and perform whiff test 1
• Treat based on confirmed diagnoses rather than empirically 1, 4

Specific Treatment by Confirmed Diagnosis

If Bacterial Vaginosis Confirmed (pH >4.5, clue cells, fishy odor)

• Metronidazole 500 mg orally twice daily for 7 days (95% cure rate) 1, 5, 2
• Alternative: Metronidazole 2 g orally single dose (84% cure rate, useful when compliance is a concern) 1, 2
• Advise patient to avoid alcohol during treatment and for 24 hours after due to disulfiram-like reaction 1, 2

If Trichomoniasis Confirmed (motile trichomonads on wet mount or positive NAAT)

• Metronidazole 2 g orally single dose 2, 4
• Treat sexual partner(s) simultaneously to prevent reinfection 2, 4

If Chlamydia or Gonorrhea Confirmed

• Chlamydia: Azithromycin 1 g orally single dose OR Doxycycline 100 mg orally twice daily for 7 days 1
• Gonorrhea: Ceftriaxone 125 mg IM single dose 1
• Partner notification and treatment is essential 1

Critical Clinical Considerations

When Empiric Treatment Is Most Appropriate

• Patient age <25 years with new or multiple sexual partners 1
• Uncertain follow-up or poor compliance anticipated 1
• High local prevalence of STIs (>5% gonorrhea prevalence) 1
• Patient anxiety about potential STI exposure warrants reassurance through treatment 1

Common Pitfalls to Avoid

• Failing to treat empirically when follow-up is uncertain: The most common STIs (trichomoniasis, chlamydia, gonorrhea, BV) account for the majority of post-sexual exposure vaginal discharge, and delayed treatment can lead to complications including pelvic inflammatory disease 1, 6
• Treating only for candidiasis: Brown discharge is rarely caused by yeast; candidiasis typically presents with white, thick discharge and normal pH (<4.5) 1, 4
• Neglecting partner treatment: For trichomoniasis and other STIs, failure to treat partners leads to reinfection 2, 4
• Not considering pregnancy: Perform pregnancy test before treatment; avoid doxycycline in pregnancy and use azithromycin instead 1

Emergency Contraception

• Offer emergency contraception if unprotected sex occurred within 120 hours 1
• Levonorgestrel 1.5 mg orally as single dose (both tablets at once) is preferred 1
• Perform baseline pregnancy test 1

Follow-Up Recommendations

• Return in 2 weeks if symptoms persist or if empiric treatment was not given initially 1
• Repeat testing for syphilis and HIV at 6-12 weeks if initial tests were negative and exposure risk was significant 1
• Test of cure is not routinely needed unless symptoms persist, pregnancy is present, or compliance is uncertain 1
• Counsel on condom use until partner treatment is completed 1