From the FDA Drug Label
PRECAUTIONS General A yellowish tinge of the skin or sclera may indicate accumulation due to impaired renal excretion and the need to discontinue therapy. NOTE : Patients should be informed that Phenazopyridine HCl produces a reddish-orange discoloration of the urine and may stain fabric Staining of contact lenses has been reported. Carcinogenesis, Mutagenesis, Impairment of Fertility Long-term administration of Phenazopyridine HCl has induced neoplasia in rats (large intestine) and mice (liver)
The side effects of Pyridium (phenazopyridine) include:
- A yellowish tinge of the skin or sclera due to accumulation
- Reddish-orange discoloration of the urine
- Staining of fabric
- Staining of contact lenses
- Potential risk of neoplasia (cancer) in the large intestine and liver, as seen in animal studies 1
From the Research
Pyridium is generally well-tolerated, but it can cause side effects, and patients should be aware of the potential risks, including orange-red discoloration of urine, headache, dizziness, and stomach upset, as well as more serious but less common side effects such as skin reactions and signs of kidney problems. The most recent and highest quality study, 2, found that phenazopyridine, the active ingredient in Pyridium, was effective and well-tolerated in patients with acute uncomplicated cystitis, with no serious adverse events reported. Common side effects of Pyridium include:
- Orange-red discoloration of urine, which is expected and harmless
- Headache
- Dizziness
- Stomach upset More serious but less common side effects include:
- Skin reactions (rash, itching)
- Yellowing of skin or eyes (jaundice)
- Dark urine not related to the orange discoloration
- Unusual tiredness
- Signs of kidney problems Rarely, patients may experience blue or purple skin discoloration, confusion, or shortness of breath. It is essential to note that Pyridium is typically used short-term (2-3 days) to relieve urinary pain and burning while waiting for antibiotics to treat underlying urinary tract infections, and patients should drink plenty of water while taking Pyridium, avoid taking it for more than 2 days unless directed by a healthcare provider, and be aware that it may stain contact lenses, clothing, and fabrics. Anyone experiencing severe side effects should seek medical attention immediately, as reported in a case study 3 where an elderly patient presented with simultaneous multiple adverse effects, including a previously undocumented myelosuppressive pancytopenia.