Phenazopyridine

 

Phenazopyridine belongs to the azo dye family, a group of synthetic compounds derived from coal tar and aromatic amines.

1920s–1930s – Emergence of Phenazopyridine 

Phenazopyridine was synthesized as part of research into derivatives of phenylazopyridine, aiming to exploit azo compounds for urinary tract conditions. Its use was found to provide symptomatic relief of dysuria (painful urination), frequency, and urgency, but unlike sulfonamides, it lacked antibacterial activity.

1940s – Clinical Introduction By the 1940s, phenazopyridine was introduced into clinical practice in the United States as a urinary tract analgesic. Its striking side effect—turning urine a bright orange-red color—quickly made it recognizable to patients and clinicians alike.

1950s–1970s – Widespread Use  Phenazopyridine became an OTC and prescription adjunct to antibiotics for urinary tract infections (UTIs). It was marketed under names like Pyridium and later AZO-Standard. 

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