What is the best antibiotic (abx) regimen for an infected intrauterine device (IUD)?

Antibiotic Treatment for Infected IUD

For infected IUDs, the recommended treatment is IUD removal plus a broad-spectrum antibiotic regimen of ceftriaxone 250 mg IM single dose PLUS doxycycline 100 mg orally twice daily for 14 days WITH metronidazole 500 mg orally twice daily for 14 days. This regimen provides necessary coverage against the polymicrobial nature of IUD-related infections.

Pathophysiology and Microbiology

IUD-related infections typically involve a polymicrobial mix of organisms including:

• Sexually transmitted pathogens (N. gonorrhoeae, C. trachomatis)
• Anaerobic bacteria
• Enterobacterales
• Other vaginal flora

The infection represents a form of pelvic inflammatory disease (PID) with the IUD serving as both a potential nidus for infection and foreign body.

Treatment Algorithm

Step 1: IUD Removal

• Remove the infected IUD promptly
• Removal is essential as antibiotics alone are unlikely to resolve the infection while the device remains in place

Step 2: Antibiotic Therapy

• First-line regimen (outpatient treatment):

  • Ceftriaxone 250 mg IM single dose
  • PLUS Doxycycline 100 mg orally twice daily for 14 days
  • WITH Metronidazole 500 mg orally twice daily for 14 days 1

• Alternative regimen (if unable to tolerate first-line):

  • Ofloxacin 400 mg orally twice daily for 14 days OR Levofloxacin 500 mg orally once daily for 14 days
  • WITH Metronidazole 500 mg orally twice daily for 14 days 1

Step 3: Inpatient Treatment (if indicated)

For severe infections or those with complications (tubo-ovarian abscess, sepsis), hospitalization and parenteral therapy are recommended:

• Parenteral Regimen A:

  • Cefotetan 2 g IV every 12 hours OR Cefoxitin 2 g IV every 6 hours
  • PLUS Doxycycline 100 mg orally or IV every 12 hours 1

• Parenteral Regimen B:

  • Clindamycin 900 mg IV every 8 hours
  • PLUS Gentamicin loading dose (2 mg/kg) followed by maintenance dose (1.5 mg/kg) every 8 hours 1

Follow-Up Recommendations

1. Patients should demonstrate substantial clinical improvement within 72 hours of initiating therapy
2. If no improvement within 72 hours, reevaluate diagnosis and consider hospitalization for parenteral therapy
3. Follow-up examination 7-10 days after completing therapy to ensure resolution
4. Consider rescreening for C. trachomatis and N. gonorrhoeae 4-6 weeks after completing therapy 1

Management of Sexual Partners

• Sexual partners should be evaluated and treated if contact occurred within 60 days preceding symptom onset
• Partners should receive empiric treatment for both chlamydial and gonococcal infections regardless of the identified pathogen in the patient 1

Common Pitfalls to Avoid

1. Treating with antibiotics without removing the IUD - The IUD must be removed as it serves as a foreign body and nidus for infection
2. Using inadequate antibiotic coverage - Single-agent therapy is insufficient; broad-spectrum coverage for polymicrobial infection is essential
3. Insufficient duration of therapy - Full 14-day course is necessary to ensure complete eradication
4. Neglecting partner treatment - Failure to treat partners increases risk of reinfection
5. Inadequate follow-up - Patients should be monitored for clinical improvement and potential complications

Special Considerations

• Pregnancy: Pregnant women with suspected IUD-related infection should be hospitalized and treated with parenteral antibiotics 1
• Alcohol interaction: Patients must avoid alcohol during metronidazole treatment and for 24 hours afterward to prevent disulfiram-like reactions 2

The evidence strongly supports that prompt IUD removal combined with appropriate antibiotic therapy is essential for successful treatment of infected IUDs, with the goal of preventing long-term sequelae such as infertility, chronic pelvic pain, and ectopic pregnancy.