Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Stop using phenazopyridine and call your doctor at once if you have any of these serious side effects:
pale skin, fever, confusion or weakness;
jaundice (yellowing of your skin or eyes);
urinating less than usual or not at all;
drowsiness, confusion, mood changes, increased thirst, loss of appetite, nausea and vomiting;
swelling, weight gain, feeling short of breath; or
blue or purple coloring in your skin.
Less serious side effects may include:
headache;
dizziness;
stomach pain, upset stomach; or
skin itching.