Medicine & USMLE


GU Drugs
  1. Phenazopyridine


Phenazopyridine is an analgesic drug that relieves pain associated with urinary tract infections. It does not directly treat the infection itself - so it is usually combined with other antibiotics. A harmless side effect of phenazopyridine is red-orange urine discoloration.

Key Points

  • Phenazopyridine
    • Mechanism
      • Analgesic
        • Contains an azo dye that, when excreted in the urine, provides a local anesthetic effect on the lining of the urinary tract
        • Should only be taken for 2 days
    • Clinical Use
      • Urinary tract infections
        • Relieves urinary pain, burning, frequency, and urgency associated with a bladder infection
        • Phenazopyridine provides pain relief, but does not treat the infection. The patient will need to additionally take a full course of antibiotics.
      • Other urinary tract pain
        • Surgery
        • Endoscopic procedures
    • Side Effects and Adverse Reactions
      • Red-orange urine discoloration
        • Expected, harmless side effect
        • Other body fluids (tears, saliva, sweat) may also turn a red-orange color
      • Hemolytic anemia
      • Renal dysfunction
      • Hepatic dysfunction