I was doing some reading on the 48hr question of phenazopyridine and I found (ontop of the methhemoglobinemia) that there is no additional benefit after 48 hours. It was mentioned that when the it is used with an antibiotic, the antibiotic will kill the bacteria that is causing the discomfort within the 48hrs and then the phenazopyridine should not be needed. Also, it can turn you skin color orange/yellow with prolonged use especially with patients with renal dysfunction.

I didn't know that APAP is an active metabolite of phenazopyridine. Thanks Chanda!