Description

Phenazopyridine hydrochloride is a medication that acts as a urinary tract analgesic. It is an azo dye that is excreted in the urine, where it exerts a local anesthetic effect on the lining of the urinary tract. It provides symptomatic relief from the pain and discomfort of urinary tract irritation but does not have any antibacterial properties and does not treat the underlying cause of the irritation or infection.

Indication

Phenazopyridine is indicated for the symptomatic relief of pain, burning, urgency, and frequency that are the result of irritation of the lower urinary tract mucosa caused by infection, trauma, surgery, endoscopic procedures, or the insertion of catheters.

It is important to note that phenazopyridine should be used as an adjunct therapy. It should not be used for more than two days when used in conjunction with an antibacterial agent to treat a urinary tract infection, as its prolonged use could mask the symptoms while the infection is still present.

Mechanism of Action

The mechanism of action of phenazopyridine is a localized, topical effect on the urinary tract.

1. Excretion in the Urine: After oral administration, phenazopyridine is rapidly absorbed and metabolized, with its metabolites and a large portion of the unchanged drug being excreted in the urine.

2. Topical Analgesic Effect: As the drug is excreted, it comes into direct contact with the mucosa (lining) of the urinary tract (bladder, ureters, urethra). It is believed to exert a direct, local anesthetic effect on the nerve endings of the mucosa.

3. Symptom Relief: By desensitizing these nerve endings, phenazopyridine reduces the sensations of pain, burning, and urgency associated with inflammation and irritation.
4. Azo Dye Properties: A key physical property of phenazopyridine is its nature as an azo dye. It colors the urine a reddish-orange or brownish-red color. This is a normal and expected effect of the medication. This discoloration can also stain clothing or contact lenses.