Background: Effective use of over-the-counter (OTC) medications depends on purchasers' knowledge of their indications. This study examines consumer knowledge regarding the urinary tract analgesic phenazopyridine, which recently became available without prescription.
Method: We conducted a cross-sectional survey of a stratified cluster random sample of purchasers of OTC phenazopyridine (N = 434) in 31 Los Angeles retail pharmacies.
Results: The response rate was 58%. Only 42% correctly characterized the likely cause of their symptoms, and only 57% correctly characterized the action of the drug. Worse consumer knowledge was associated with nonwhite race, first-time use, and less contact with health providers.
Conclusion: Many consumers possess poor knowledge about phenazopyridine, potentially leading to undertreatment, especially in groups with worse access to care.