Phenazopyridine is an oral urinary tract analgesic. It is used for the symptomatic relief of pain, burning, urgency, frequency, and other discomforts resulting from irritation of the lower urinary tract mucosa, including symptomatic relief of urinary tract infection (UTI) symptoms. Phenazopyridine is an azo dye that is excreted in the urine; thus, the urine is discolored orange or red during use. The use of phenazopyridine for the relief of urinary symptoms should not delay definitive diagnosis and treatment of causative conditions; prompt appropriate treatment of the cause of pain must be instituted. Phenazopyridine may be used with antibacterial therapy and can help to relieve pain and discomfort during the interval before antibacterial therapy controls the UTI. Treatment of the symptoms of a UTI with phenazopyridine should not exceed 2 days because there is a lack of evidence that the combined administration with an antibacterial provides greater benefit than administration of the antibacterial alone after 2 days. Phenazopyridine is available in prescription and non-prescription dosage forms and has been used clinically for decades. Rare cases of methemoglobinemia and hemolytic anemia have been reported with use of phenazopyridine; patients with G6PD deficiency or with renal insufficiency should not take phenazopyridine.
General Administration Information
For storage information, see the specific product information within the How Supplied section.
Route-Specific Administration
Oral Administration
-Administer phenazopyridine with or after meals to minimize GI discomfort.
-Administer with a full glass of water.
-Do not administer for longer than directed; most patients will take the drug for no more than 2 days.
Extemporaneous Compounding-Oral
Extemporaneous compounding instructions for Phenazopyridine oral suspension 10 mg/mL:
An oral suspension yielding 10 mg/mL may be formulated according to the following procedure:
-Crush three phenazopyridine 200 mg tablets and mix with a small amount of distilled water or glycerin.
-Then, add 20 mL of Cologel and levigate until a uniform mixture is obtained.
-Add sufficient 2:1 simple syrup/cherry syrup mixture to make a final volume of 60 mL.
-Store in an amber container. Preparation is stable for 60 days under refrigeration.
-Shake well before each use.
-For accurrate dose measurement, use a calibrated oral syringe, spoon, or other calibrated oral measuring device. Give dose with or after meals and with a full glass of water.
Methemoglobinemia and hemolytic anemia have been reported with use of phenazopyridine, usually following an overdose. However, these adverse events have also been reported with usual therapeutic dosages in the setting of renal impairment or end stage renal disease. Methemoglobinemia results from exposure to chemicals that oxidize the iron in hemoglobin from its ferrous to its ferric state. Concomitant oxidation of hemoglobin protein may cause its precipitation (as Heinz bodies) and a hemolytic anemia (with bite cells seen on peripheral blood smear). Administer methylene blue intravenously if a patient develops methemoglobinemia. Although the manufacturer recommends oral ascorbic acid as an alternative to methylene blue, ascorbic acid reduces methemoglobinemia at a slower rate and is therefore less effective.
Acute renal failure (e.g., renal tubular necrosis) may rarely occur with use of phenazopyridine. Patients with preexisting renal disease may be predisposed to the development of renal failure. A few cases of hepatotoxicity also have been reported. A dose-related toxic hepatitis has been observed, as well as a hypersensitivity-mediated hepatitis associated with elevated hepatic enzymes, jaundice, fever and eosinophilia. Aseptic meningitis has also been reported.
Phenazopyridine is an azo dye and can discolor many bodily fluids. It can cause contact lens discoloration and, because it is excreted in the urine, can cause urine discoloration.
Adverse reactions reported with use of phenazopyridine include headache, rash (unspecified), pruritus, anaphylactoid reactions, and gastrointestinal disturbances.
Phenazopyridine should not be used in patients who have previously exhibited previous phenazopyridine hypersensitivity.
The use of phenazopyridine for relief of urinary symptoms should not delay the definitive diagnosis and treatment of causative conditions. Because phenazopyridine only provides symptomatic relief, appropriate treatment of the cause of pain must be initiated and phenazopyridine should be discontinued when symptoms are controlled.
Phenazopyridine should not be used for more than 2 days in a patient being treated for a urinary tract infection. There is no evidence that the combined administration of phenazopyridine and an antibacterial provides greater benefit than administration of the antibacterial alone after 2 days.
Phenazopyridine is contraindicated in patients with renal impairment, including renal failure. Patients with renal disease should consult with their doctor prior to use. In other patients, a yellowish tinge of the skin or sclera during therapy may indicate accumulation of the drug due to impaired renal excretion. If this occurs, the drug should be discontinued. Because renal function may decline with advancing age, phenazopyridine should be used with caution in geriatric patients.
Use of phenazopyridine can cause methemoglobinemia or hemolytic anemia. Because glucose-6-phosphate dehydrogenase deficiency (G6PD deficiency) may predispose to hemolysis, phenazopyridine should not be used in this patient population unless under close supervision of their health care provider.
Phenazopyridine is an azo dye. Phenazopyridine produces an orange to red color in the urine and may stain fabric. The staining of the urine is not harmful, but care should be taken to prevent stains on clothing. Irreversible staining of soft contact lenses has been reported.
There are no adequate and well-controlled studies of phenazopyridine use in pregnant women. Reproduction studies in rats at doses up to 50 mg/kg/day have revealed no evidence of impaired fertility or harm to the fetus; however, because animal reproduction studies are not always predictive of human response, phenazopyridine should be used during pregnancy only if clearly needed. Self-treatment by women of child-bearing potential is not recommended unless pregnancy testing confirms a lack of pregnancy. Awoman who is pregnant should consult her health care provider before use.
It is not known whether phenazopyridine is excreted in human milk. Cases of acquired methemoglobinemia in infants after phenazopyridine ingestion have been reported. Phenazopyridine and its metabolites (i.e., aniline) may have the potential to produce methemoglobinemia. Therefore, it is prudent to avoid phenazopyridine use while breast-feeding, especially with an infant less than 1 month of age or has a glucose-6-phosphate dehydrogenase (G6PD) deficiency.
Due to its properties as an azo dye, phenazopyridine may cause laboratory test interference with urinalysis based on spectrometry or color reactions. Laboratory tests which may be affected include urinary glucose tests and urinary ketone tests.
For the symptomatic relief of dysuria, urinary urgency, irritation, and other discomforts of the lower urinary tract caused by infection, trauma, surgery, endoscopic procedures, or the passage of sounds or catheters:
Oral dosage:
Adults: 190 to 200 mg PO 3 times daily with or after meals. When used non-prescription or concomitantly with an antibacterial agent for the treatment of a urinary tract infection, use should not exceed 2 days. For short-term use only; discontinue when symptoms are controlled.
Children and Adolescents 12 to 17 years: 190 to 200 mg PO 3 times daily with or after meals. When used non-prescription or concomitantly with an antibacterial agent for the treatment of a urinary tract infection, use should not exceed 2 days. For short-term use only; discontinue when symptoms are controlled.
Children 6 to 11 years*: Safety and efficacy have not been established; off-label use has been described. Use should be by prescription of a health care professional; do not self-treat. Dose used: 4 mg/kg/dose PO 3 times daily with or after meals for up to 2 days.
Maximum Dosage Limits:
-Adults
600 mg/day PO.
-Geriatric
600 mg/day PO.
-Adolescents
600 mg/day PO.
-Children
12 years: 600 mg/day PO.
6 to 11 years: Safety and efficacy have not been established; however, 12 mg/kg/day PO has been reported.
1 to 5 years: Safety and efficacy have not been established.
-Infants
Safety and efficacy have not been established.
-Neonates
Safety and efficacy have not been established.
Patients with Hepatic Impairment Dosing
Dosage adjustment is recommended; however, specific guidelines are not available. Phenazopyridine is metabolized in the liver to potentially active and/or toxic metabolites.
Patients with Renal Impairment Dosing
CrCl > 80 ml/min: No dosage adjustment is needed.
CrCl 50-80 ml/min: Administer dose every 8-16 hours.
CrCl < 50 ml/min: Avoid use.
*non-FDA-approved indication
There are no drug interactions associated with Phenazopyridine products.
The mechanism of action of phenazopyridine has not been fully determined. Phenazopyridine is an azo dye that is excreted in the urine and exerts a topical analgesic or local anesthetic effect on the mucosa of the urinary tract. It possesses no antibacterial actions.
Phenazopyridine is administered orally. The pharmacokinetic disposition of phenazopyridine has not been fully established. Trace amounts of the drug are believed to cross the placenta and to enter the CSF. Metabolism of phenazopyridine probably occurs in the liver; one of the metabolites is acetaminophen. The drug is rapidly excreted by the kidneys, with as much as 65% of an oral dose excreted unchanged in the urine.