@sarahmartinez817, thank you

Here's what I could find on the subject, link to the site I used at the bottom of the post. I'm not a doctor, though, so you should verify with your pediatrician to be certain.

Summary of Use during Lactation:

The safety of phenazopyridine is not established in infants or during breastfeeding. Because it can cause methemoglobinemia, sulfhemoglobinemia, and hemolytic anemia, it should be avoided while breastfeeding, especially with an infant under 1 month of age or with G-6-PD deficiency.

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