Phenazopyridine

Phenazopyridine is a urinary tract analgesic used to relieve pain, burning, urgency, and discomfort associated with irritation of the lower urinary tract. It is not an antibiotic and does not treat infection; it provides symptom relief while an underlying cause is addressed by a clinician.

It is typically used for short-term symptomatic relief rather than as a treatment for infection. In many regimens, adults take a short course of 200 mg three times daily after meals, with duration often limited to about two days unless directed by a healthcare professional. Formulations and instructions can vary.

Mechanism and pharmacology: The exact analgesic mechanism is not fully understood, but phenazopyridine is thought to exert a local anesthetic–like effect on the mucosa of the urinary tract. The drug is rapidly absorbed and excreted in urine, which causes the characteristic urine discoloration.

Adverse effects and safety: The most notable effect is orange to red discoloration of urine, which can stain clothing and contact lenses. Other possible side effects include stomach upset, headache, and dizziness. Rare but serious risks include methemoglobinemia and hemolytic anemia, particularly in individuals with G6PD deficiency or significant kidney impairment. Hypersensitivity reactions can occur.

Contraindications and interactions: The medication is contraindicated in those with known hypersensitivity to phenazopyridine and should be used with caution in people with severe kidney disease. It should be used with caution during pregnancy or breastfeeding and only under medical supervision when needed. Phenazopyridine can interfere with certain urine and laboratory tests; patients should inform providers about its use. It is intended to be used in conjunction with appropriate treatment for the underlying condition if an infection is present.