Phenazopyridine (Pyridium, Azo): Uses and Safety
Quick summary: Phenazopyridine is a urinary tract pain-relief medicine used to help ease burning, urgency, and discomfort in the lower urinary tract. It is known for turning urine orange or red. Common U.S. brand...
This content is for educational purposes only and does not replace medical advice, diagnosis or treatment from a qualified healthcare professional.
Quick summary: Phenazopyridine is a urinary tract pain-relief medicine used to help ease burning, urgency, and discomfort in the lower urinary tract. It is known for turning urine orange or red.
Common U.S. brand names: Pyridium, Azo Urinary Pain Relief, Azo-Standard, and Uristat.
Medical disclaimer: This article is for general information only and does not replace the official product leaflet, a pharmacist’s advice, or guidance from a licensed clinician. Do not use this page to diagnose a condition or to decide on treatment changes.
What is phenazopyridine?
Phenazopyridine hydrochloride is an active ingredient used to relieve symptoms of irritation in the urinary tract. It is not described here as a cure for the underlying cause of symptoms, but as a medicine that helps reduce discomfort.
It is commonly associated with urinary symptoms such as burning, pain, urgency, and frequent urination.
How phenazopyridine works
The exact mechanism of action is not known. The available information indicates that it is excreted in the urine and produces a local anesthetic effect on the mucous membrane of the urinary tract.
What phenazopyridine is used for
Phenazopyridine is used to help relieve symptoms such as:
- Pain in the urinary tract
- Burning or irritation when urinating
- Urgent need to urinate
- Frequent urination
- Discomfort related to urinary tract infections, surgery, injuries, or tests
It has also been described as an auxiliary analgesic in urinary tract conditions such as pyelitis, pyelonephritis, urethritis, and uretrotrigonitis.
Another well-known effect is that it can make urine appear orange or red.
Common brand names
In the United States, phenazopyridine is sold under brand names including:
- Pyridium
- Azo Urinary Pain Relief
- Azo-Standard
- Uristat
Dosage forms mentioned in the source
Phenazopyridine is taken orally. The source lists tablet strengths of:
- 95 mg
- 100 mg
- 200 mg
The original content states that dosing and duration are determined by the physician and that use is not recommended for more than 15 consecutive days.
Important safety information
| Topic | What the source says |
|---|---|
| Kidney problems | Contraindicated in renal insufficiency and oliguria. |
| Liver problems | Contraindicated in hepatic insufficiency and hepatitis. |
| Other conditions | The source also lists glomerulonephritis, gastrointestinal disorders, and a history of enzyme deficiency methemoglobulinemia. |
| Pregnancy | Caution is advised; pyelonephritis associated with pregnancy is listed as a contraindication in the source. |
| Children | Children under 12 years are noted as requiring physician supervision. |
Warnings and precautions
- Possible allergy to phenazopyridine or related medicines.
- Possible interactions with prescription medicines, over-the-counter products, and vitamins.
- Caution in people with kidney disease or G6PD deficiency.
- Caution during pregnancy.
- Caution in people with liver disease under treatment.
- Urine may turn reddish-orange, which should be expected and explained to patients.
Contraindications listed in the source
- Known hypersensitivity to phenazopyridine or its metabolites
- Renal insufficiency
- Oliguria
- Glomerulonephritis
- Hepatic insufficiency
- Hepatitis
- Pyelonephritis associated with pregnancy
- Gastrointestinal disorders
- History of enzyme deficiency methemoglobulinemia
Interactions and test interference
Phenazopyridine may interfere with some laboratory urine tests. The source notes possible interference with urinalysis based on spectrometry or color reactions.
It may also affect tests for albumin and ketones depending on the method used, and it may cause false positive reactions in glucose and porphyrin testing.
Possible side effects
The source lists the following adverse reactions:
- Headache
- Dizziness
- Confusion
- Yellowing of the skin or eyes
- Skin discoloration, including blue to blue-purple coloring
- Rash
- Upset stomach
- Fever
- Dyspnea
- Sudden oliguria
- Swelling of the face, fingers, feet, or legs
What to verify with a doctor or pharmacist
If you are reviewing phenazopyridine for yourself or someone else, it is sensible to confirm the following with a healthcare professional or the official leaflet:
- Whether the symptoms need medical evaluation rather than symptom relief alone
- Whether any kidney or liver condition changes the safety of use
- Whether pregnancy or a child’s age changes the recommendation
- Whether any urine test may be affected
- Whether the product label matches the intended use and strength
FAQ
▸ What is phenazopyridine used for?
It is used to help relieve urinary tract discomfort such as burning, pain, urgency, and frequent urination.
▸ Does phenazopyridine treat the cause of a urinary tract infection?
The source describes it as a medicine for symptom relief. It is presented as an auxiliary analgesic, not as a cure for the underlying cause.
▸ Why does phenazopyridine change urine color?
The source states that it can make urine appear orange or red. This is a known effect that should be explained to patients.
▸ Can phenazopyridine affect urine tests?
Yes. The source says it may interfere with some urinalysis methods and can affect certain test results depending on the technique used.
▸ Who should be cautious with phenazopyridine?
The source highlights caution in people with kidney disease, liver disease, G6PD deficiency, pregnancy, and in children under 12 years.
▸ What are the main warning signs to watch for?
The source lists yellowing of the skin or eyes, blue-purple skin discoloration, fever, dyspnea, swelling, and sudden reduced urine output among possible adverse reactions.
Safety reminder: If urinary symptoms are severe, persistent, or accompanied by fever, flank pain, blood in the urine, or reduced urine output, seek medical advice promptly. Always check the official product leaflet and speak with a pharmacist or clinician if you are unsure whether phenazopyridine is appropriate.
Sources and references
The original content states that the information was prepared using clinical and molecular data from medicines authorized and marketed in the United States under the Unique Ingredient Identifier (UNII), along with FDA and USP-related resources.
Medical disclaimer
This content is for educational purposes only. It should not be used as a substitute for professional medical advice, diagnosis or treatment. Always ask a doctor, pharmacist or qualified healthcare professional before starting, stopping or changing any medicine.
Sources and verification
The following sources or official references are listed to support verification of the medicine information discussed in this article.
Medicine information can change and may vary depending on country, product formulation, patient history and professional guidance. Always check official medicine information and ask a healthcare professional for personal medical questions.