AZO Urinary Pain Relief

Uses

AZO Urinary Pain Relief is a local anesthetic used for the symptomatic relief of pain, burning, urgency, frequency, and general discomfort caused by lower urinary tract irritations that are a result of infection, trauma, surgery, endoscopic procedures, or the passage of equipment or catheters.

AZO Urinary Pain Relief hydrochloride is indicated to relieve uncomfortable symptoms that occur as a consequence of mucosal irritation of the lower urinary tract in adults. The irritation may be a result of trauma, surgery, endoscopic procedures, infection, or the insertion of instruments or urinary catheters. AZO Urinary Pain Relief may be used in combination with antimicrobial therapy but is not used as an antimicrobial agent. It contributes to the relief of discomfort and pain before antimicrobial therapy begins to take effect. It is important to note that the duration of treatment with this drug should last a maximum of 2 days. AZO Urinary Pain Relief is available in many countries as an over the counter drug.

AZO Urinary Pain Relief is also used to associated treatment for these conditions: Lower Urinary Tract Infection, Signs or symptoms of urinary tract irritation

How AZO Urinary Pain Relief works

The full mechanism of action of phenazopyridine is not fully elucidated, however, it is reported to exert a direct topical analgesic effect on the mucosal lining of the urinary tract via the inhibition of voltage-gated sodium channels and possibly group A nerve fibers, as suggested by the results of a study in rats. The above actions likely lead to the relief of unpleasant urinary symptoms.

Toxicity

The oral LD50 of phenazopyridine in rats is 472 mg/kg.

Overdose information

Administering excess phenazopyridine above the daily recommended dose in those with healthy or impaired kidney function may increase the drug concentration and predispose the patient to toxicity. When a large overdose occurs, methemoglobinemia results. To treat this condition, Methylene blue at 1 to 2 mg/kg/dose should be administered intravenously as a 1% solution as deemed necessary. Its administration is likely to cause a rapid reduction of the methemoglobinemia state and relieve the associated cyanosis. Hemolytic anemia is also a risk when an overdose occurs, and “bite cells” may be observed in a blood smear after an overdose with phenazopyridine. Red blood cell G6PD deficiency may increase the risk of hemolysis, and even normal doses can lead to methemoglobinemia in patients with this condition. Nephrotoxicity, renal failure, and hepatic impairment may also occur in a case of overdose with this drug. Administer symptomatic and supportive treatment as necessary.

Food Interaction

• Take with food. Food reduces irritation.

AZO Urinary Pain Relief Drug Interaction

Unknown: diphenhydramine, diphenhydramine, duloxetine, duloxetine, omega-3 polyunsaturated fatty acids, omega-3 polyunsaturated fatty acids, pregabalin, pregabalin, acetaminophen, acetaminophen, cyanocobalamin, cyanocobalamin, ascorbic acid, ascorbic acid, cholecalciferol, cholecalciferol, alprazolam, alprazolam, cetirizine, cetirizine

AZO Urinary Pain Relief Disease Interaction

Major: G-6-PD deficiency, hepatitis, renal dysfunction

Volume of Distribution

Small, trace quantities of phenazopyridine are thought to cross the placenta and the blood-brain barrier, reaching cerebrospinal fluid. A pharmacokinetic study in rats determined that phenazopyridine metabolites were present in high levels in the kidney and liver.

Elimination Route

AZO Urinary Pain Relief is absorbed in the gastrointestinal tract. The mean Cmax is 65.00 ± 29.23 ng/mL, the mean Tmax is 2.48 ± 0.50 h, and the mean AUC(0 – ∞)is 431.77 ± 87.82 ng.h/mL.

Half Life

The mean elimination half-life of phenazopyridine is 7.35 hours in rats with healthy renal function. The half-life in man is not readily vailable in the literature.

Clearance

This drug is rapidly excreted by the kidneys, up to 65% of a dose administered orally may be excreted as unchanged drug in the urine. The clearance of phenazopyridine may be decreased with impaired renal or hepatic function and is contraindicated in these conditions.

Elimination Route

Up to 65% of an oral phenazopyridine dose is quickly excreted by the kidneys as unchanged drug measured in the urine. The pharmacokinetics of this drug have not been evaluated in depth in man. In a small group of healthy research volunteers, 90% of a daily 600 mg oral dose of phenazopyridine hydrochloride was found to be excreted within 1 day, with 41% as unchanged drug and 49% as phenazopyridine metabolites. Another study in humans determined that 80.07 ± 4.54 percent of the dose was cleared in the urine within 48 hours of administration. In rats, biliary excretion was high, with 40.7% of a dose excreted in 8 hours.

Innovators Monograph

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