PHENAZOPYRIDINE HYDROCHLORIDE TABLETS, USP

The pharmacokinetic properties of Phenazopyridine hydrochloride have not been determined. Phenazopyridine and its metabolites are rapidly excreted by the kidneys. In a small number of healthy subjects, 90% of a 600 mg/day oral dose of Phenazopyridine hydrochloride was eliminated in the urine in 24 hours, 41% as unchanged drug and 49% as metabolites.

The patient should be advised that Phenazopyridine produces an orange to red color in the urine and feces, and may cause staining. Phenazopyridine may cause discoloration of body fluids and staining of contact lenses has been reported. A yellowish color of the skin or sclera may indicate accumulation of Phenazopyridine resulting from impaired renal function and necessitates discontinuance of the drug. It should be noted that a decline in renal function is common in elderly patients. Phenazopyridine may mask pathological conditions and interfere with laboratory test values using colorimetric, spectrophotometric or fluorometric analysis methods.

Cautious use in patients with G-6-PD deficiency is advised since these patients are susceptible to oxidative hemolysis and may have greater potential to develop hemolytic anemia.

The patient should be advised to take Phenazopyridine with or following food or after eating a snack to reduce stomach upset.

The patients should be aware that Phenazopyridine causes a reddish orange discoloration of the urine and feces, and may stain clothing. Phenazopyridine may cause discoloration of body fluids and staining of contact lenses has been reported. There have been reports of teeth discoloration when the product has been broken or held in the mouth prior to swallowing.

Patients should be instructed to take Phenazopyridine for only 2 days if an antibacterial agent is administered concurrently for the treatment of a urinary tract infection. If symptoms persist beyond those 2 days, the patient should be instructed to contact his or her physician.

Phenazopyridine may interfere with laboratory test values using colorimetric, photometric or fluorometric analysis methods.

Altered urine laboratory test values may include ketone (sodium nitroprusside) bilirubin (foam test, talc-disk-Fouchet-spot test, Franklin's tablet-Fouchet test, p-nitrobenzene diazonium p-toluene sulfonate reagent), diacetic acid (Gerhardt ferric chloride test), free hydrochloric acid, glucose (glucose oxidase tests), 17-hydroxycorticosteroids (modified Glenn-Nelson), 17-ketosteroids (Holtorff Koch modification of Zimmerman), porphyrins, albumin (discolors bromophenol blue test areas of commercial reagent strips, nitric acid ring test), phenolsulfophthalein, urobilinogen (color interference with Ehrlich's reagent), and urinalysis (spectrophotometric or color-based tests). Phenazopyridine also imparts an orange-red color to stools which may interfere with color tests.

The interaction of Phenazopyridine with other drugs has not been studied in a systematic manner. However, the medical literature to date suggests that no significant interactions have been reported.

Long-term administration of Phenazopyridine has been associated with tumors of the large intestine in rats and of the liver in mice. Available epidemiological data are insufficient to evaluate the carcinogenicity of Phenazopyridine in humans. In vitro studies indicate that Phenazopyridine in the presence of metabolic activation is mutagenic in bacteria and mutagenic and clastogenic in mammalian cells.

Reproductive studies with Phenazopyridine (in combination with sulfacytine) in rats given up to 110 mg/kg/day and in rabbits given up to 39 mg/kg/day during organogenesis revealed no evidence of harm to offspring.

One prospective study in humans demonstrated that Phenazopyridine traverses the placenta into the fetal compartment. There are no adequate and well-controlled studies in pregnant women. Therefore, Phenazopyridine should be used in pregnant women only if the benefit clearly outweighs the risk.

It is not known whether Phenazopyridine or its metabolites are excreted in human milk. Because many drugs are excreted in human milk, a decision should be made to discontinue nursing or to discontinue the drug, taking into account the importance of drug therapy to the mother.

Adequate and well-controlled studies have not been performed in the pediatric population. No pediatric-specific problems have been documented.

Store at 20° to 25°C (68° to 77°F); excursions permitted to 15° to 30°C (59° to 86°F). [See USP Controlled Room Temperature].

NDC 71205-835-06 100 mg, 6 count

NDC 71205-835-10 100 mg, 10 count

NDC 71205-835-12 100 mg, 12 count

NDC 71205-835-20 100 mg, 20 count

NDC 71205-835-24 100 mg, 24 count

NDC 71205-835-90 100 mg, 90 count

NDC 71205-835-96 100 mg, 96 count

NDC 71205-835-00 100 mg, 100 count

NDC 71205-835-55 100 mg, 500 count

Appearance: Deep brown to maroon colored, round, film coated tablets debossed "G-15" on one side and plain on the other.

NDC 71205-836-06 200 mg, 6 count

NDC 71205-836-10 200 mg, 10 count

NDC 71205-836-12 200 mg, 12 count

NDC 71205-836-20 200 mg, 20 count

NDC 71205-836-24 200 mg, 24 count

NDC 71205-836-90 200 mg, 90 count

NDC 71205-836-96 200 mg, 96 count

NDC 71205-836-00 200 mg, 100 count

NDC 71205-836-55 200 mg, 500 count

Appearance: Deep brown to maroon colored, round, film coated tablets debossed "G-17" on one side and plain on the other.