Pyridium Side Effects: What to Expect and When to Call Your Doctor

Pyridium (phenazopyridine) is highly effective for relieving the burning, urgency, and pain of urinary tract infections — but it does come with some notable side effects. Most are harmless and expected. A few require medical attention. Here's exactly what to expect when you take it.

The Most Common Side Effect: Orange or Red Urine

This is the side effect almost everyone notices: phenazopyridine turns your urine a vivid orange or reddish color. This is completely expected and harmless — it simply means the drug is doing what it's supposed to do (being excreted into your urine where it works).

Important things to know about the urine discoloration:

It can permanently stain underwear, clothing, and bed sheets. Use dark-colored underwear while taking this medication.

It can permanently stain soft contact lenses. Do not wear contact lenses while taking phenazopyridine.

The discoloration can interfere with urine test results (dipstick tests based on color). Inform any lab or provider that you are taking phenazopyridine before submitting a urine sample.

Other Common Side Effects

In addition to urine discoloration, some patients experience:

Upset stomach or nausea: The most common GI complaint. Taking phenazopyridine with food or after a meal significantly reduces this risk. Always take with a full glass of water.

Headache: Reported by some patients, usually mild.

Dizziness: Mild dizziness has been reported. If it's significant or persistent, contact your doctor.

Serious Side Effects: Stop Taking It and Call Your Doctor

These side effects are uncommon but require prompt medical attention. Stop taking phenazopyridine immediately and contact your healthcare provider if you experience:

Yellow skin or yellow eyes (jaundice): This indicates drug accumulation from reduced kidney function. It is a signal to stop the medication immediately. Older adults and those with any kidney impairment are at higher risk.

Shortness of breath, confusion, or bluish skin: These can be signs of methemoglobinemia — a rare but potentially serious blood disorder where red blood cells can't carry oxygen properly. Seek emergency care immediately.

Skin rash, hives, or difficulty breathing: Signs of an allergic reaction. Stop the medication and seek medical care promptly.

Fever, confusion, severe swelling: Contact your provider — these are not typical phenazopyridine effects and may suggest worsening infection or another complication.

Who Is at Higher Risk for Serious Side Effects?

Certain patients are at elevated risk for serious reactions:

Kidney disease: Phenazopyridine should not be taken by anyone with kidney disease. Since ~65% of the drug is excreted unchanged in urine, impaired kidneys lead to accumulation and toxicity.

G6PD deficiency: An inherited enzyme deficiency affecting red blood cells. Phenazopyridine can trigger hemolytic anemia in these patients.

Older adults: Age-related kidney changes mean older patients are more susceptible to drug accumulation. Monitoring for yellowing of skin or eyes is especially important in this group.

Patients on prilocaine or benzocaine: Combining phenazopyridine with these local anesthetics significantly raises the risk of methemoglobinemia.

How to Minimize Side Effects

Always take with food to reduce nausea

Drink a full glass of water with each dose

Do not wear contact lenses while taking phenazopyridine

Use dark-colored underwear to prevent staining

Do not take for more than 2 days with an antibiotic; longer use can mask worsening infection

The Bottom Line

Orange urine is normal and expected with phenazopyridine. Nausea can be managed by taking the medication with food. The serious side effects — yellow skin, breathing difficulty, allergic reaction — are rare but require you to stop the medication and seek care. For drug interaction specifics, see our Pyridium drug interactions guide. If you're still searching for your phenazopyridine prescription, medfinder can help locate it near you.