Phenazopyridine side effects and drug information

Phenazopyridine is a medication that is used to treat any discomfort brought about by irritation or infection or the urinary tract, relieve pain, burning, and anything associated with the urinary problem. The medication is not an antibiotic, and it will never cure the infection on its own. 

ATC code G04BX06 (WHO)
Formula C11H11N5
ChemSpider ID 4592
CAS ID 94-78-0
Molar Mass 213.239 g/mol


Phenazopyridine is a drug that works as a pain reliever that helps treat the lower part of the urinary tract area, especially the urethra and bladder. It is used to remedy urinary symptoms like burning, pain, frequent urination, and the urge to urinate. These symptoms can be caused by injury, surgery, infection, or catheter that may have irritated one’s bladder. 

The medication can treat any urinary symptoms. However, this medicine will never treat your UTI or urinary tract infection. Take your antibiotic that your physician prescribes to treat the UTI or urinary tract infection. Phenazopyridine can be used for purposes not indicated in the medication guide. 

Before taking Phenazopyridine

You must not utilize Phenazopyridine if you are allergic to it or any inactive ingredients it may have or where you have kidney problems. 

To ensure your Phenazopyridine use is 100% safe, inform your doctor when you have – 

  • Diabetes
  • Liver disease
  • Have G6PD deficiency or also known as glucose-6-phosphate dehydrogenase, a genetic enzyme deficiency.

It is uncertain if Phenazopyridine can harm an unborn child. However, always seek your doctor’s advice if you intend to use it while pregnant. It is unknown too whether Phenazopyridine can pass into breast milk or if it can harm a baby that is nursing. Do not attempt to use the medicine if you are actively breastfeeding a baby.

Side Effects

Phenazopyridine can cause some unwanted side effects on the body. But, not all of these side effects can happen to you, in case they do, immediately seek medical attention. 

Ask your doctor or healthcare provider as soon as possible if any of these side effects happen while they are taking Phenazopyridine.

Common Phenazopyridine Side Effects

  • Fever
  • Confusion
  • Bluish skin color
  • Shortness of breath
  • Difficulty breathing
  • Wheezing
  • Skin rashes
  • Swelling of feet, legs, face or fingers
  • Sudden decrease amount of urine
  • Extreme fatigue
  • Tremors
  • Yellowish skin or eyes
  • Weight gain

Many of the side effects of Phenazopyridine happen that often do not require any medical attention. The side effects can quickly go away after some time as soon as the body adjusts to the drug. Also, your medical doctor or pharmacist will be able to advise you about ways you can prevent or minimize the symptoms and side effects of taking the drug. Ask your medical doctor or pharmacist if you have experienced any of the following serious side effects such as:

Serious Side Effects of Phenazopyridine

Dosage and Administration

The dosage of Phenazopyridine will vary on a case to case basis and from one patient to another. Ensure that you follow your doctor’s orders closely or any of the directions provided for in the product label that is found on the packaging. Outlined here are the information consisting of the typical doses of Phenazopyridine. If your Phenazopyridine dose is different, do not worry or attempt to change it, unless of course, when your doctor tells you otherwise. 

The medication that you finally take will also depend on the potency of the drug. Moreover, the number of doses you have to take daily, the time interval between doses, length of time to take medicine, can all depend on the medical problem for which you are being treated with the aid of the drug. 

Oral Tablets Dosage

  • For pain, burning, and other discomfort brought about by the urinary tract –


  • 200 milligrams 3 x a day.


  • Dosing will be based on the child’s body weight and will be further determined by the physician. The typical dosing is 4 milligrams per KG of bodyweight 3 x a day. 

Follow exactly as directed on the medicine label or as prescribed by your medical doctor. Do not use bigger or smaller amounts or for an extended period than recommended. Take medicine after each meal.

Phenazopyridine will darken your urine color and make it red or orange as the case may be. This is but normal and is never harmful. The drug can cause a permanent stain in your underwear too. Also, it can cause permanent staining on contact lenses, avoid wearing them as you take the medication. Avoid using the drug for more than two days except when your doctor told you so. The medicine can cause some odd results on your urine tests. Inform your doctor when you are using the drug and if you are required to take urine tests. 

Phenazopyridine Missed Dose

Should you forget to take a dose of Phenazopyridine, take it as soon as you remember. But, if it is almost time for the next dose, skip the missed dose altogether and follow the regular dosing schedule as provided. Never take double doses.

Phenazopyridine Storage

Store Phenazopyridine in an airtight container at room temperature. Keep it away from direct heat, moisture, or cold temperatures. Keep out of pet and children’s reach.

Drug Interaction

Different medications require different storage requirements. Always read the product label found on the packaging on how to properly store your Dulcolax medicine. Keep your drug away from pets and children’s reach at all times. Never flush out your medication down the toilet or the drain unless when you are told to do so. Follow proper ways of discarding your medication found on the product packaging when no longer in need or when the product expires. Ask your doctor or pharmacist for proper waste disposal.

Other Interactions

There are particular medications that must not be used at or the same time of eating food, or consuming certain foods as interactions can happen. The use of alcohol or tobacco with certain drugs is likewise prohibited as it can cause interactions. Ask your healthcare provider if you use the drug with food, tobacco, or alcohol. 

Other medical problems can affect your use of the medication. You have to tell your physician if you have medical problems, such as:

  • Kidney disease
  • Hepatitis
  • G6PD deficiency

Warnings and Precautions

Ask your doctor if you have certain symptoms like difficult or painful passing of urine, bloody urine, frequent urination, or a sudden decrease in the urine amount you expel while you are taking the medication.

Phenazopyridine can cause urine discoloration from orange to red. This is a natural side effect of the medicine. This is 100% harmless and will go away the moment you stop taking the medication.

Patients with soft contact lenses 

Do not wear your contact lenses when under treatment with Phenazopyridine. It can cause some discoloration and stains on your soft contact lens. It will not be possible to remove it, and the staining can be permanent.

Patients with diabetes  

This medicine can result in a false test result with your urine sugar testing and urine ketone tests. If you have concerns, ask your doctor or pharmacists, especially if you have a bad case of diabetes.

Before you take any medical examinations or tests, inform the one in charge that you are taking Phenazopyridine. The results of your tests can be impacted by Phenazopyridine use.

Before you take the medication, inform your physician if you have allergies to any of its ingredients. Phenazopyridine medicine can contain certain inactive ingredients that can lead to some allergic reactions. Ask your pharmacist or doctor for more information.

Phenazopyridine must not be used if you are suffering from some medical issues. Before you do, ask your doctor, especially if you have anemia, G6PD deficiency, kidney disease, liver disease, or any blood disorders. Before you take Phenazopyridine, inform your healthcare provider about your medical history. 

Phenazopyridine can cause dizziness. You should not use any machinery, drive, or perform any undertaking that can impact your focus or alertness. Do not use alcohol, marijuana, or any intoxicating substance while using Phenazopyridine for any treatment.

Phenazopyridine can cause discoloration to your urine and tears. It can turn to orange or red hue. It can also stain your contact lenses and clothing. Never wear contact lenses while under treatment with Phenazopyridine. Your tears and urine will go back to their normal color after you have stopped using Phenazopyridine.

Inform your doctor if you are pregnant before you try to use this medication.

Overdose and Contraindications

When someone you know has overdosed or has very serious symptoms like trouble breathing, passing out, or more, call a doctor or pharmacist for immediate medical assistance. You can also call on the poison control center immediately. Residents from the USA can call on their local poison control center for assistance. Serious symptoms of overdose can include persistent nausea, vomiting, diarrhea, stomach pain, or cramps. Never share this medication with another person even if they have symptoms similar to you. 

The drug has been prescribed for your condition only. Never take any other pain reliever for your urinary tract problem unless you have consulted with your doctor. A different drug may be needed under this circumstance.