Phenazopyridine

Phenazopyridine is an analgesic agent belonging to the pharmacological class of azo dyes or urinary analgesics.

The FDA approves Phenazopyridine to alleviate symptoms of dysuria, burning sensations, urgency, frequency, and pain linked to lower UTIs.

Phenazopyridine absorbs in the gastrointestinal tract, reaching the cerebrospinal fluid and placenta. Liver metabolism generates acetaminophen and 5-hydroxyl PAP. The kidneys eliminate 65% through urine.

The common side effects of Phenazopyridine include headache, nausea, vomiting, diarrhea, rash, and urine discoloration.

Phenazopyridine is available as a tablets.

The molecule is available in India, Brazil, the United States, Canada, the United Kingdom, Australia, Germany, France, Italy, Japan, and Mexico.

Phenazopyridine is an analgesic agent belonging to the pharmacological class of azo dyes or urinary analgesics.

While Phenazopyridine's exact mode of action is still unknown, research on rats suggests that it may work by directly inhibiting voltage-gated sodium channels and group A nerve fibres to produce a topical analgesic effect on the urinary tract mucosa. Painful urinary symptoms are probably relieved by those previous measures.

The time required for Phenazopyridine to show its effect is usually within an hour after administration.

The time duration for Phenazopyridine generally lasts for about 3 to 4 hours.

Phenazopyridine's maximum plasma concentration (Cmax) generally occurs around 1 to 2 hours post-administration.

(Tmax)for Phenazopyridine after administration has not been established.

Phenazopyridine is available as a tablets.

Tablets: To be swallowed whole with water/liquid. Do not chew, crush or break it.

As the physician recommends, take the medication orally thrice daily, as directed.

Phenazopyridine can be used for various health conditions:

By reducing the pain, discomfort, and urgency induced by urinary tract irritation, Phenazopyridine provides symptomatic relief. While not curing the underlying problem, it reduces symptoms while a patient receives treatment. Acting as a local analgesic, it relaxes the urinary tract's lining and reduces discomfort related to urination. While treating the underlying disease, this medicine improves comfort by temporarily relieving pain, burning sensations, and frequent or urgent urinating.

Orally: Phenazopyridine tablets are typically administered orally, with or without food. However, they are preferable to take after meals to minimize stomach upset. The doctor determines the dosage, usually taken three times a day. Drink plenty of fluids during treatment to aid in flushing the urinary tract. If a dose is missed, take it as soon as remembered; however, avoid doubling it to compensate for the missed one.

The dosage and duration of treatment should be as per the treating physician's clinical judgment.

Phenazopyridine is available in the form of tablets.

Dysuria, Irritation of Lower Urinary Tract Mucosa

Three times a day, 100–200 mg PO after meals

Never take an antibiotic for a UTI concurrently for more than two days.

Due to reduced renal function, limit dosage in the elderly group.

It is essential to avoid certain meals and beverages when using Phenazopyridine, as these include alcohol, caffeine, and spicy or acidic foods that may cause discomfort. Maintaining adequate hydration is crucial to avert methemoglobinemia and subsequent renal issues. Choose a plant-based diet, regular exercise, and pelvic floor exercises to strengthen bladder muscles and control body weight. Furthermore, while phenazopyridine medication, stopping smoking is crucial for maintaining bladder function and general health.

The dietary restriction should be individualized as per patient requirements.

Phenazopyridine may be contraindicated in the following conditions:-

The adverse reactions related to Phenazopyridine can be categorized as

Common Adverse Effects: Orange-colored urine, headache, dizziness.

Less Common Adverse Effects: Upset stomach and skin rash or itching.

Rare Adverse Effects: Methemoglobinemia, hepatic/renal toxicity, staining of contact lenses and hemolytic anaemia

The clinically relevant drug interactions of Phenazopyridine are briefly summarized here.

The common side effects of Phenazopyridine include: -

Vomiting

Headache

Dizziness

Stomach cramp

Nausea

Diarrhoea

Changes in urine colour

Upset stomach

Pregnancy Category B (FDA): Could be acceptable. Either no danger has been shown by animal research, but human studies have yet to be conducted, or some risk has been shown by animal studies but not by human studies.

No evidence of harm to offspring was found in reproductive trials involving Phenazopyridine (in conjunction with sulfacytine) in rats given up to 110 mg/kg/day and in rabbits given up to 39 mg/kg/day during organogenesis.

According to a single, minimal prospective research conducted on humans, Phenazopyridine crosses the placenta and enters the fetal compartment. More reliable, well-controlled research on expectant mothers is needed. Phenazopyridine should, therefore, only be administered to expectant mothers in situations where the advantages much exceed the risks.

It is unknown if the drug is excreted in human milk. Because many drugs are excreted in human milk, precaution should be exercised.

As per the FDA, the safety and efficacy of Phenazopyridine in pediatric patients have yet to be extensively studied or established.

Dysuria and Lower Urinary Tract Mucosal Irritation

<6 Years: No safety or efficacy data available

6–12 years: divided every 8 hours, 12 mg/kg/day PO after meals

Over 12 years old: three times a day, 100–200 mg PO after meals

If you have a UTI, do not take concurrently with antibiotics for more than two days.

As per the FDA, the safety and efficacy of Phenazopyridine in elderly patients above 65 have not been extensively studied or established.

Phenazopyridine is contraindicated in patients with renal insufficiency.

Phenazopyridine is contraindicated in patients with any liver disease.

The physician should be vigilant about the knowledge pertaining to the identification and treatment of overdosage of Phenazopyridine.

Overconsumption of Phenazopyridine could lead to methemoglobinemia, hemolysis, acute renal failure, and potential hepatic toxicity.

There is no specific antidote or treatment for excessive Phenazopyridine, so treatment typically involves symptomatic and supportive measures. If ingestion is recent, gastric lavage or activated charcoal might be considered to limit absorption.

Unless directed by a healthcare professional, avoid inducing vomiting. Supportive care involves treating symptoms and taking steps to prevent complications. In cases of methemoglobinemia, administer methylene blue intravenously at a dose of 1 to 2 mg/kg as a 1% solution or give 100-200 mg oral ascorbic acid as required, to swiftly reduce methemoglobinemia and resolve cyanosis, aiding in diagnosis. Monitor renal function and maintain hydration to prevent acute renal failure. Hemodialysis may be necessary in severe cases or to manage potential hepatic toxicity. Regularly check for adverse effects, especially hemolysis and liver damage. Ensure sufficient hydration and monitor renal function due to potential kidney-related issues.