What is the appropriate ciprofloxacin (Cipro) dosing regimen for an adult with an uncomplicated urinary tract infection, no fluoroquinolone allergy, normal renal function, and not pregnant?

Ciprofloxacin Dosing for Uncomplicated UTI

For an uncomplicated urinary tract infection (cystitis) in an adult with normal renal function, ciprofloxacin 250 mg orally twice daily for 3 days is the appropriate dose, but it should only be used as a second-line agent when nitrofurantoin or trimethoprim-sulfamethoxazole cannot be used and local fluoroquinolone resistance is below 10%. 1

First-Line Therapy (Not Ciprofloxacin)

Before prescribing ciprofloxacin, you should attempt first-line agents:

• Nitrofurantoin 100 mg orally twice daily for 5 days is the preferred first-line treatment due to minimal collateral damage to normal flora and low resistance rates 1
• Trimethoprim-sulfamethoxazole 160/800 mg orally twice daily for 3 days is acceptable only when local resistance is documented below 20% 1

Fluoroquinolones like ciprofloxacin should be reserved as alternative agents because they promote antimicrobial resistance (including MRSA) and cause significant collateral damage to the microbiome 1

Ciprofloxacin Dosing Options for Uncomplicated Cystitis

When first-line agents are contraindicated or inappropriate:

• Standard regimen: Ciprofloxacin 250 mg orally twice daily for 3 days 1, 2
• Extended-release alternative: Ciprofloxacin 500 mg extended-release once daily for 3 days 1, 3

Both regimens achieve approximately 93-94% bacteriologic cure and 93-96% clinical cure rates 1, 3

Critical Resistance Threshold

Do not use ciprofloxacin empirically if local fluoroquinolone resistance exceeds 10%. 1 Verify your local antibiogram before prescribing. This is a hard stop—if resistance is above this threshold, choose a different agent.

Common Pitfalls to Avoid

• Never use single-dose ciprofloxacin therapy: A one-time dose leads to significantly lower efficacy (89% vs 93-98%) and higher relapse rates compared to 3-day therapy 2
• Do not extend to 7 days for uncomplicated cystitis: Longer courses increase adverse events without improving cure rates 1, 2
• Avoid amoxicillin/ampicillin empirically: These have universally high resistance rates and poor efficacy for UTIs 1

If This Were Pyelonephritis Instead

The dosing would be completely different:

• Ciprofloxacin 500 mg orally twice daily for 7 days for acute pyelonephritis 4, 1
• Consider adding a single IV dose of ceftriaxone 1 g if local fluoroquinolone resistance exceeds 10% 4, 1
• Extended-release option: Ciprofloxacin 1000 mg extended-release once daily for 7 days 4, 1, 5

Summary Algorithm

1. Confirm uncomplicated cystitis (no fever, flank pain, or systemic symptoms)
2. Check local fluoroquinolone resistance (<10% required) 1
3. Attempt first-line agents first: nitrofurantoin or TMP-SMX 1
4. If first-line contraindicated: Prescribe ciprofloxacin 250 mg orally twice daily for 3 days 1, 2
5. Alternative for convenience: Ciprofloxacin 500 mg extended-release once daily for 3 days 1, 3