Cotrimoxazole Dosing for Chronic Cystitis
For chronic cystitis, the recommended dose of cotrimoxazole (trimethoprim/sulfamethoxazole) is 160/800 mg (one double-strength tablet) twice daily for 10-14 days. 1, 2
Dosing Recommendations
- For urinary tract infections in adults, including chronic cystitis, the standard dosage is one double-strength tablet (160/800 mg) or two single-strength tablets (80/400 mg) every 12 hours for 10-14 days 1, 2
- Dosing must be adjusted in patients with renal impairment:
Efficacy Considerations
- Cotrimoxazole remains highly effective for treating urinary tract infections when the causative organism is susceptible, with clinical cure rates of 84-100% 3
- Treatment efficacy is significantly reduced when the infection is caused by resistant organisms (84% cure rate with susceptible organisms vs. 41% with resistant organisms) 3
- Local resistance patterns should be considered before prescribing cotrimoxazole; it should only be used empirically when local resistance rates are below 20% 3
Treatment Duration for Chronic Cystitis
- While acute uncomplicated cystitis may be treated with a 3-day course of cotrimoxazole, chronic cystitis requires a longer duration of 10-14 days 1, 2
- Despite guideline recommendations for shorter courses in acute cystitis, studies show that physicians commonly prescribe 10-day courses for both acute and recurrent infections 4
Alternative Options
- If local resistance rates exceed 20% or the patient has risk factors for resistant organisms, consider alternative agents:
- Nitrofurantoin monohydrate/macrocrystals (100 mg twice daily for 5-7 days) 3
- Fluoroquinolones (3-day regimens) - though these should be reserved for cases where other options cannot be used due to potential for collateral damage 3
- β-lactam agents (3-7 day regimens) when other recommended agents cannot be used 3
Monitoring and Follow-up
- For chronic cystitis, urine culture and susceptibility testing should be performed before initiating therapy to guide appropriate antibiotic selection 3
- Follow-up urine cultures may be necessary to confirm eradication of infection, especially in cases of chronic or recurrent infection 5
- Monitor for adverse effects, which occur in approximately 8-15% of patients taking cotrimoxazole 6
Common Pitfalls to Avoid
- Using cotrimoxazole empirically in areas with high resistance rates (>20%) can lead to treatment failure 3
- Underdosing or using too short a treatment course for chronic cystitis may result in persistent infection 5
- Failing to adjust dosage in patients with renal impairment increases the risk of adverse effects 1, 2
- Not obtaining cultures before treatment in chronic or recurrent cases may lead to inappropriate antibiotic selection 3