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Phenazopyridine (Systemic)


VA CLASSIFICATION
Primary: GU100

Commonly used brand name(s): Azo-Standard; Baridium; Eridium; Geridium; Phenazo; Phenazodine; Pyridiate; Pyridium; Urodine; Urogesic; Viridium.

Note: For a listing of dosage forms and brand names by country availability, see Dosage Forms section(s).



Category:


Analgesic (urinary)—

Indications

Accepted

Urinary tract irritation (treatment)—Phenazopyridine is indicated for short-term use to relieve symptoms such as pain, burning, and urinary urgency and/or frequency caused by irritation of the lower urinary tract mucosa. The underlying cause of the irritation must be determined and treated (for example, antibacterial therapy for infection). {01} {02}{14}


Pharmacology/Pharmacokinetics

Physicochemical characteristics:

Chemical group—
    Azo dye. {01} {02}
Molecular weight—
    249.70 {03}

Mechanism of action/Effect:

Exerts a topical analgesic or local anesthetic action on the urinary tract mucosa. The exact mechanism of action is unknown. {01}

Biotransformation:

Probably hepatic; also in other tissues. {04} One of the metabolites is acetaminophen. {05}

Elimination:
    Renal. Up to 90% of a dose is excreted within 24 hours, as unchanged drug and metabolites. About 18% of a dose is eliminated as acetaminophen. {05} Up to 65% of a dose may be excreted unchanged. {01}


Precautions to Consider

Carcinogenicity

Long-term administration of phenazopyridine has caused neoplasia of the large intestine in rats and neoplasia of the liver in mice. No association between use of the medication in humans and development of neoplasia has been reported; however, studies in humans have not been done. {01} {02}

Pregnancy/Reproduction
Fertility—
Studies in rats with doses up to 50 mg per kg of body weight (mg/kg) per day have not shown evidence of impaired fertility. {01} {02}

Pregnancy—
Adequate and well-controlled studies have not been done in humans. {01} {02}

Studies in rats with doses up to 50 mg/kg per day have not shown evidence of harm to the fetus. {01} {02}

FDA Pregnancy Category B. {01}

Breast-feeding

It is not known whether phenazopyridine or any of its metabolites are distributed into breast milk. {01} {02} However, problems in humans have not been documented.

Pediatrics

Appropriate studies with phenazopyridine have not been performed in the pediatric population. However, no pediatrics-specific problems have been documented to date.


Geriatrics


Although appropriate studies with phenazopyridine have not been performed in the geriatric population, no geriatrics-specific problems have been documented to date. However, elderly patients are more likely to have age-related renal function impairment, which may increase the risk of accumulation and toxicity in patients receiving phenazopyridine.


Laboratory value alterations
The following have been selected on the basis of their potential clinical significance (possible effect in parentheses where appropriate)—not necessarily inclusive (» = major clinical significance):

With physiology/laboratory test values
Urinalyses based on color reaction or spectroscopy {01} {02}{14} , for example:
Bilirubin, urine, determined via foam test, talc-disk–Fouchetspot test, or Franklin"s tablet-Fouchet test methods {06}
Glucose, urine, determined using glucose oxidase {06}
17-Hydroxycorticosteroids, urine, determined via Glenn-Nelson method {06}
Ketones, urine, determined using sodium nitroprusside or Gerhardt ferric chloride test {06}
17-Ketosteroids, urine, determined via Haltorff Koch modification of Zimmerman reaction {06}
Kidney function tested via phenolsulfonphthalein (PSP) excretion {06}
Protein, urine, determined using bromophenol blue test reagent strips or nitric acid ring test {06}
Urobilinogen, urine, determined using Ehrlich"s reagent {06}    (phenazopyridine may interfere with test results by causing discoloration of the urine {01} {02} {06})


Medical considerations/Contraindications
The medical considerations/contraindications included have been selected on the basis of their potential clinical significance (reasons given in parentheses where appropriate)— not necessarily inclusive (» = major clinical significance).


Except under special circumstances, this medication should not be used when the following medical problem exists:
Renal function impairment {01}{14}    (increased risk of accumulation and toxicity)


Risk-benefit should be considered when the following medical problems exist
Allergic reaction to phenazopyridine, history of {01}{14}
» Glucose-6-phosphate dehydrogenase (G6PD) deficiency    (increased risk of severe hemolytic anemia {07} {08})


Hepatitis {01}    (increased risk of adverse effects)




Side/Adverse Effects

Note: In addition to the side effects reported below, an anaphylactoid-like reaction has been reported. {01}{14}

The following side/adverse effects have been selected on the basis of their potential clinical significance (possible signs and symptoms in parentheses where appropriate)—not necessarily inclusive:

Those indicating need for medical attention
Incidence rare
    
Anemia, hemolytic (troubled breathing, exertional; unusual tiredness or weakness)
    
aseptic meningitis (fever; confusion)—reported in 1 patient; causal relationship verified via rechallenge {11}
    
dermatitis, allergic (skin rash)
    
hepatotoxicity (yellow eyes or skin)
    
methemoglobinemia (blue or blue-purple discoloration of skin; shortness of breath)
    
renal function impairment or failure (increased blood pressure; shortness of breath; troubled breathing; tightness in chest, and/or wheezing; sudden decrease in amount of urine; swelling of face, fingers, feet, and/or lower legs ; thirst, continuing; unusual tiredness or weakness; weight gain)
Note: Hemolytic anemia or methemoglobinemia may be more likely with an overdose or if the medication is administered to patients with renal function impairment, {01}{14} but have also been reported with therapeutic doses in patients with normal renal function. {09} {10} Also, hemolytic anemia is especially likely to occur in patients with glucose-6-phosphate dehydrogenase deficiency. {07} {08}
Hepatotoxicity has been reported in conjunction with impaired renal excretion of the medication; however, yellowish discoloration of eyes or skin may also occur independently of hepatotoxicity, indicating accumulation. Permanent staining of soft contact lenses has also been reported. {01} {13}





Those indicating need for medical attention only if they continue or are bothersome
Incidence less frequent or rare
    
Dizziness
    
headache {04}
    
indigestion {01}
    
pruritus (itching of the skin)
    
stomach cramps or pain {01}





Overdose
For more information on the management of overdose or unintentional ingestion, contact a poison control center (see Poison Control Center Listing).

Clinical effects of overdose
The following effects have been selected on the basis of their potential clinical significance (possible signs and symptoms in parentheses where appropriate)—not necessarily inclusive:

Anemia, hemolytic (troubled breathing, exertional; unusual tiredness or weakness)

hepatotoxicity (yellow eyes or skin)

methemoglobinemia (blue or blue-purple discoloration of skin; shortness of breath)

renal function impairment or failure ( increased blood pressure; shortness of breath; troubled breathing; tightness in chest, and/or wheezing; sudden decrease in amount of urine; swelling of face, fingers, feet, and/or lower legs; thirst, continuing ; unusual tiredness or weakness; weight gain)

Specific treatment
Methemoglobinemia will respond to methylene blue intravenous, 1 to 2 mg per kg of body weight or ascorbic acid oral, 100 to 200 mg. The resulting reduction in methemoglobinemia and cyanosis is an aid in diagnosing phenazopyridine overdose.{14}

Patients in whom intentional overdose is confirmed or suspected should be referred for psychiatric consultation.


Patient Consultation
As an aid to patient consultation, refer to Advice for the Patient, Phenazopyridine (Systemic).

In providing consultation, consider emphasizing the following selected information (» = major clinical significance):

Before using this medication
»   Conditions affecting use, especially:
Allergic reaction to phenazopyridine, history of
Other medical problems, especially glucose-6-phosphate dehydrogenase (G6PD) deficiency

Proper use of this medication
Taking with or following food (a meal or a snack) to reduce gastric upset

» Not using any saved portion of medication in the future unless authorized by physician

» Proper dosing
Missed dose: Taking as soon as possible; not taking if almost time for next dose; not doubling doses

» Proper storage

Precautions while using this medication
» Informing physician if symptoms worsen

» Medication causes urine to turn reddish orange and may stain clothing

Not wearing soft contact lenses during therapy because of possible permanent staining

Diabetics: May cause false urine sugar and urine ketone test results

Possible interference with laboratory test results; notifying person in charge that medication is being used


Side/adverse effects
Signs of potential side effects, especially allergic dermatitis, aseptic meningitis, hemolytic anemia, hepatotoxicity, methemoglobinemia, and renal impairment or failure


General Dosing Information
This medication should be taken with or following food to lessen gastric irritation.

When phenazopyridine is used concurrently with an antibacterial agent in the treatment of a urinary tract infection, the duration of phenazopyridine therapy should not exceed 2 days. Adequate evidence that more prolonged phenazopyridine therapy provides greater therapeutic benefit than is achieved with the antibacterial agent alone is not available. {01}{14}


Oral Dosage Forms

PHENAZOPYRIDINE HYDROCHLORIDE TABLETS USP

Usual adult and adolescent dose
Analgesic (urinary)
Oral, 200 mg three times a day, with or following food. {01} {02}{14}

Note: When used in combination with an antibacterial agent for the treatment of urinary tract infection, length of phenazopyridine treatment should not exceed two days.{14}



Usual pediatric dose
Analgesic (urinary)
Oral, 4 mg per kg of body weight three times a day, with food. {04}


Strength(s) usually available
U.S.—


100 mg (Rx) [Azo-Standard] [Baridium] [Eridium] [Geridium] [Phenazodine] [Pyridiate] [Pyridium] [Urodine] [Urogesic][Generic]


200 mg (Rx) [Geridium] [Phenazodine] [Pyridiate] [Pyridium] [Urodine] [Viridium][Generic]

Canada—


100 mg (OTC) [Phenazo] [Pyridium]


200 mg (OTC) [Phenazo] [Pyridium]

Packaging and storage:
Store below 40 °C (104 °F), preferably between 15 and 30 °C (59 and 86 °F), unless otherwise specified by manufacturer. Store in a tight container.

Auxiliary labeling:
   • May discolor urine.
   • Take with food.

Note: Stains on clothing may be removed with a 0.25% solution of sodium dithionate or sodium hydrosulfite.




Revised: 12/17/1999



References
  1. Pyridium (Parke-Davis), in: Physician"s desk reference 46th ed. 1992: 1763-4. (information prepared 8/91).
  1. Pyridium (Parke-Davis), in: Krogh CME, ed. Compendium of pharmaceuticals and specialties 26th Ed. Ottawa: Canadian Pharmaceutical Association; 1991: 1006.
  1. Fleeger CA, editor. USAN and the USP dictionary of drug names. Rockville, MD: The U.S. Pharmacopeial Convention, Inc. 1992: 470.
  1. McEvoy GK, Ed. AHFS drug information. Bethesda: American Society of Hospital Pharmacists; 1992: 2156-7.
  1. Johnson WJ, Chartrand A. The metabolism and excretion of phenazopyridine hydrochloride in animals and man. Toxicol Appl Pharmacol 1976; 37: 371-6.
  1. Hansten PD. Drug interactions. Philadelphia: Lea & Febiger; 1971: 345, 360, 371, 374, 377, 386, 394.
  1. Mercieca JE, Clarke MG, Phillips ME, Curtis JR. Acute haemolytic anaemia due to phenazopyridine hydrochloride in G-6-PD deficient subject. The Lancet 1982; 2: 564 (letters).
  1. Galun E, Oren R, Glikson M, Friedlander M, Heyman A. Phenazopyridine-induced hemolytic anemia in G-6-PD deficiency. Drug Intell Clin Pharm 1987; 21: 921-2 (letters).
  1. Jeffery WH, Zelicoff AP, Hardy WR. Acquired methemoglobinemia and hemolytic anemia after usual doses of phenazopyridine. Drug Intell Clin Pharm 1982; 16: 157-9.
  1. Loughner JE, Bennett JM. Acquired acute hemolytic anemia secondary to phenazopyridine. Drug Intell Clin Pharm 1980; 14: 861-3.
  1. Herlihy T. Phenazopyridine and aseptic meningitis. Ann Intern Med 1987; 106: 172-3 (letters).
  1. Bigby M, Jick S, Hick H, Arndt K. Drug-induced cutaneous reactions. A report from the Boston collaborative drug surveillance program on 15,438 consecutive inpatients, 1975 to 1982. JAMA 1986; 256: 3358-63.
  1. Communication to Drug Product Problems Reporting Division, United States Pharmacopeial Convention.
  1. Product Information: Pyridium, phenazopyridine. Warner Chilcott Laboratories, Rockaway, NJ, USA, Rev. 06/1998
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