What Antibiotics Treat UTIs?

First-Line Antibiotics for Uncomplicated UTIs

Current medical guidelines recommend several antibiotics as first-line treatments for uncomplicated lower urinary tract infections. Here's what you should know about each.

1. Nitrofurantoin (Macrobid)

• Dosage: 100mg twice daily for 5 days
• How it works: Concentrates in the urine and damages bacterial DNA
• Pros: Narrow spectrum (targets urinary bacteria without disrupting gut flora), low resistance rates
• Cons: Must be taken with food, not suitable for kidney infections
• Avoid if: Kidney disease (CrCl < 30), G6PD deficiency

2. Trimethoprim-Sulfamethoxazole (Bactrim DS)

• Dosage: 160/800mg twice daily for 3 days
• How it works: Blocks two steps of bacterial folate synthesis
• Pros: Short course, well-studied, inexpensive
• Cons: Sulfa allergies are common, increasing resistance in some areas
• Avoid if: Sulfa allergy, pregnancy (1st trimester), taking warfarin or methotrexate

3. Fosfomycin (Monurol)

• Dosage: 3g single dose (one packet dissolved in water)
• How it works: Blocks bacterial cell wall synthesis
• Pros: Single-dose convenience, good for patients with multiple drug allergies
• Cons: Slightly lower cure rates than multi-day regimens, more expensive

4. Ciprofloxacin (Cipro) - Reserve Agent

• Dosage: 250mg twice daily for 3 days
• How it works: Fluoroquinolone - inhibits bacterial DNA replication
• Pros: Broad spectrum, effective
• Cons: FDA black box warnings for tendon damage, nerve damage, and other serious side effects. Reserved for when first-line agents are not appropriate

Important Notes

• Complete the full course even if symptoms improve before you finish
• Symptom relief typically begins within 24-48 hours
• Stay hydrated while taking antibiotics
• Report persistent symptoms - if you don't improve within 48-72 hours, you may need a different antibiotic or further evaluation
• Probiotics can help prevent antibiotic-associated digestive side effects

How UTIDOC Selects Your Antibiotic

Our system uses your allergy history, current medications, and clinical guidelines to recommend the safest and most effective antibiotic for your specific situation. A physician reviews every case before any prescription is issued.