UTI Prophylaxis After Intercourse
For women with recurrent UTIs associated with sexual activity, post-coital antibiotic prophylaxis taken within 2 hours of intercourse is the recommended first-line preventive strategy. 1, 2
Recommended Prophylactic Regimens
First-line options:
- Nitrofurantoin 50-100 mg taken within 2 hours after intercourse
- Trimethoprim-sulfamethoxazole (TMP-SMX) 40/200 mg taken within 2 hours after intercourse
- Trimethoprim 100 mg taken within 2 hours after intercourse
Alternative options (if allergies or resistance patterns warrant):
- Fosfomycin trometamol (single dose every 10 days)
- Cephalexin (125 mg post-coital)
Duration of Prophylaxis
- Initial duration of 6-12 months is recommended
- Reassess effectiveness and need for continuation periodically
- Some women may require longer durations based on recurrence patterns
Non-Antibiotic Alternatives
For patients concerned about antibiotic use or those with contraindications:
- Methenamine hippurate 1g twice daily (creates bacteriostasis in acidic urine) 2
- Lactobacillus-containing probiotics (especially for postmenopausal women) 1
- Vaginal estrogen therapy (for postmenopausal women) 2
Behavioral Modifications
These should be implemented alongside pharmacological prophylaxis:
- Voiding completely after intercourse
- Maintaining adequate hydration (2-3L daily)
- Avoiding prolonged urine retention
- Avoiding sequential anal and vaginal intercourse
- Avoiding spermicides (which can disrupt normal vaginal flora) 1
Important Considerations
Patient Selection
Post-coital prophylaxis is specifically indicated for women with:
- ≥3 UTIs per year or ≥2 UTIs in 6 months
- Clear temporal relationship between UTIs and sexual activity 1, 2
Antibiotic Stewardship
- Choose antibiotics based on previous culture results and local resistance patterns
- Nitrofurantoin is preferred when possible due to low resistance rates 1
- Avoid fluoroquinolones for prophylaxis unless specifically indicated by resistance patterns 1
Monitoring
- Monitor for adverse effects (GI disturbances, rash, pulmonary/hepatic toxicity with nitrofurantoin)
- Consider periodic urine cultures during treatment breaks to assess for resistant organisms
- Do not perform surveillance cultures in asymptomatic patients 1
Special Populations
Postmenopausal Women
- Consider vaginal estrogen therapy with or without antibiotics
- Estrogen helps restore vaginal microbiome and reduces vaginal atrophy 2
Pregnant Women
- Requires specialized approach - consult with OB/GYN
- Post-coital prophylaxis may still be appropriate but medication selection differs
The evidence strongly supports post-coital antibiotic prophylaxis as an effective strategy, with studies showing reduction in UTI recurrence rates from 3.6 per patient-year with placebo to 0.3 per patient-year with post-coital TMP-SMX 3. This approach is as effective as daily prophylaxis but with reduced antibiotic exposure 4, 5.