What is the recommended treatment for cystitis, particularly when caused by a bacterial infection?

Treatment of Bacterial Cystitis

For uncomplicated bacterial cystitis in women, prescribe short-course antibiotics with either nitrofurantoin for 5 days, trimethoprim-sulfamethoxazole (TMP-SMZ) for 3 days, or fosfomycin as a single dose. 1, 2

First-Line Treatment Options for Uncomplicated Cystitis

Recommended Regimens:

• Nitrofurantoin monohydrate/macrocrystals: 100 mg twice daily for 5 days 1, 2
• Trimethoprim-sulfamethoxazole (TMP-SMZ): 160/800 mg (double-strength tablet) twice daily for 3 days 1, 2
• Fosfomycin trometamol: 3 g single dose 2

Important Considerations for Antibiotic Selection:

• TMP-SMZ should only be used when local resistance rates are below 20% and the patient has no history of recent TMP-SMZ use or international travel 2
• Nitrofurantoin is preferred in areas with high TMP-SMZ resistance but should be avoided in patients with renal impairment (GFR <30 ml/min) 2
• Fluoroquinolones (5-7 days) should be reserved as second-line agents due to concerns about promoting resistance 1, 3

Treatment for Special Populations

Pregnant Women:

• Nitrofurantoin: 100 mg twice daily for 5-7 days (avoid in third trimester and with renal impairment) 2

Patients with Renal Impairment:

• Avoid nitrofurantoin if GFR <30 ml/min 2
• Adjust TMP-SMZ dosing in severe renal impairment 4

Patients with Pyelonephritis:

• TMP-SMZ: 14 days (if susceptible) 2
• Fluoroquinolones: 5-7 days 2
• Consider initial IV dose of ceftriaxone (1g) if susceptibility unknown 2

Monitoring and Follow-up

• Evaluate clinical response within 48-72 hours of initiating therapy 2
• No routine follow-up urine culture needed in patients who respond to therapy 2
• Follow-up urine culture should be performed 7 days after completing treatment in cases of persistent symptoms 2

Common Pitfalls to Avoid

1. Overtreatment Duration: Prolonged courses increase risk of side effects and resistance without improving outcomes 2
2. Inappropriate Antibiotic Selection: Using broad-spectrum antibiotics when narrow-spectrum would suffice 1, 3
3. Treating Asymptomatic Bacteriuria: This increases antibiotic resistance without clinical benefit 2
4. Ignoring Local Resistance Patterns: TMP-SMZ should not be used empirically in areas with >20% resistance 2, 5
5. Missing Drug Interactions: TMP-SMZ can interact with warfarin, phenytoin, and methotrexate, and may cause hyperkalemia 4

Prevention Strategies for Recurrent Cystitis

• Increased fluid intake (additional 1.5L daily) 2
• Urinating after sexual activity if infections are related to sexual intercourse 2
• Avoiding spermicides 2
• Cranberry products containing 36 mg proanthocyanidin may have modest efficacy 2, 6

For patients with frequent recurrences, antibiotic prophylaxis options include nitrofurantoin 50-100 mg daily or TMP-SMZ at reduced frequency, but this should be considered only after other measures fail 2.