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Phenazopyridine (AZO): Uses, Dosage, and Safety Information

Last reviewed: December 2025

Overview

Phenazopyridine (brand names AZO, Pyridium, Uristat) is a urinary tract analgesic that provides rapid relief from the pain, burning, and urgency caused by urinary tract infections (UTIs). It does NOT treat the infection—only the symptoms. You still need antibiotics to cure a UTI.

What Is Phenazopyridine?

Phenazopyridine is a local anesthetic that works directly on the urinary tract lining. It numbs the irritated tissue, providing relief from uncomfortable UTI symptoms within hours.

Key facts:

  • Provides symptom relief only—not a treatment
  • Works within 20-30 minutes
  • Available OTC and by prescription
  • Causes orange/red discoloration of urine

Common Brand Names

Over-the-counter:

  • AZO Urinary Pain Relief
  • Uristat
  • AZO Standard
  • Store brands

Prescription:

  • Pyridium
  • Phenazopyridine (generic)
  • Higher strengths than OTC

What It Treats

UTI symptoms:

  • Burning sensation during urination
  • Pain or discomfort while urinating
  • Urinary urgency (feeling like you need to go NOW)
  • Urinary frequency (needing to go often)
  • Bladder pressure or cramping

What it does NOT treat:

  • The bacterial infection itself
  • Kidney infections
  • Sexually transmitted infections
  • Any underlying cause

How It Works

Phenazopyridine works locally in the urinary tract:

  1. Excreted in urine after being absorbed
  2. Directly contacts and numbs urinary tract lining
  3. Reduces inflammation signals locally
  4. Provides anesthetic effect on irritated tissue

This is why it works quickly—it acts directly where the problem is.

Important Warnings

It Does Not Treat the Infection

Critical: Phenazopyridine only relieves symptoms. You MUST see a doctor and take antibiotics to cure a UTI. Using phenazopyridine without antibiotics allows the infection to worsen and potentially spread to your kidneys.

Duration Limits

  • OTC use: Maximum 2 days
  • Prescription: As directed, usually not more than 2-3 days
  • If symptoms persist beyond 2 days, see a doctor

Urine Discoloration

  • Turns urine bright orange or red-orange
  • This is normal and expected
  • May stain underwear and contact lenses
  • Resolves when you stop taking it

Who Should Avoid Phenazopyridine

Do not use if you have:

  • Kidney disease
  • Liver disease
  • Allergy to phenazopyridine
  • G6PD deficiency

Use with caution if:

  • Pregnant or breastfeeding (consult doctor)
  • Elderly (may need lower doses)
  • Taking other medications

When to See a Doctor

Seek medical care if you have:

  • Fever (sign of kidney infection)
  • Back or side pain
  • Nausea or vomiting
  • Blood in urine (not from the medication)
  • Symptoms lasting more than 2 days
  • Recurrent UTIs
  • First UTI (need proper diagnosis)

Always get antibiotics for confirmed UTI—phenazopyridine is only for temporary comfort.

Common Side Effects

  • Orange/red urine (expected)
  • Headache
  • Stomach upset
  • Dizziness

Serious side effects (rare):

  • Yellowing of skin/eyes
  • Skin discoloration
  • Shortness of breath
  • Blue/purple skin color

Stop use and seek medical care for serious side effects.

Drug Interactions

  • May interfere with urine tests (tell healthcare providers you’re taking it)
  • Generally few significant drug interactions
  • Tell your doctor about all medications

Storage

  • Store at room temperature
  • Keep away from moisture
  • Keep out of reach of children

Sources

  • FDA — Phenazopyridine Drug Information
  • UpToDate — Phenazopyridine: Drug Information
  • American Urological Association — UTI Guidelines
  • AZO Product Information
Last reviewed: December 2025