From the Guidelines
Pyridium works as a urinary analgesic by directly soothing the urinary tract lining, providing pain relief without treating the underlying infection or inflammation. The medication's mechanism of action is not fully understood, but it is believed to act locally on the mucosa of the urinary tract after being excreted into the urine, exerting a topical anesthetic effect on the urinary tract epithelium, reducing pain, burning, urgency, and discomfort during urination 1.
Key Points
- Pyridium is commonly used to alleviate symptoms of interstitial cystitis/bladder pain syndrome, although data in the literature are limited, and individual patients may find it worthwhile in alleviating symptoms 1.
- The medication produces a distinctive orange-red color in urine, which patients should be warned about to prevent alarm.
- Pyridium provides symptomatic relief only and should always be combined with appropriate antibiotic therapy when treating urinary tract infections.
- It should be used cautiously in patients with renal impairment since it can accumulate and potentially cause toxicity.
Dosage and Administration
- Pyridium is typically prescribed at 100-200 mg three times daily for no more than 2 days when used with antibiotics for urinary tract infections.
- Prolonged use can mask symptoms of ongoing infection, and therefore, it is essential to limit the duration of treatment.
From the FDA Drug Label
CLINICAL PHARMACOLOGY Phenazopyridine HCl is excreted in the urine where it exerts a topical analgesic effect on the mucosa of the urinary tract. This action helps to relieve pain, burning, urgency and frequency. The precise mechanism of action is not known. The mechanism of action of Pyridium (phenazopyridine) is not known, but it is believed to exert a topical analgesic effect on the mucosa of the urinary tract 2.
From the Research
Mechanism of Action of Pyridium (Phenazopyridine)
- Pyridium, also known as phenazopyridine, is a urinary tract analgesic that works by acting on the bladder mucosa to produce a local analgesic effect 3.
- The exact mechanism of action is not fully understood, but it is believed to involve the inhibition of prostaglandin synthesis, which contributes to the reduction of pain and inflammation in the urinary tract 4, 5.
- Phenazopyridine has been shown to decrease the severity of pain and discomfort associated with urinary tract infections, including cystitis, by reducing the production of prostaglandins and other inflammatory mediators 4, 5.
Clinical Evidence
- Several studies have demonstrated the efficacy and safety of phenazopyridine in the treatment of acute uncomplicated cystitis, including a multicenter, randomized, placebo-controlled study that showed significant improvements in pain relief and symptom reduction 4, 5.
- A study comparing the combination of fosfomycin and phenazopyridine to the combination of fosfomycin and drotaverine found that the phenazopyridine combination was more effective in reducing symptoms and improving patient outcomes 5.
- However, a review of the clinical evidence for urinary tract analgesics, including phenazopyridine, noted that the published evidence is scarce, and more studies are needed to fully understand the effectiveness and safety of these medications 6.
Safety and Adverse Effects
- Phenazopyridine is generally well-tolerated, with a low incidence of adverse effects, including nausea and headache 4, 5, 7.
- A safety analysis of long-term phenazopyridine use for radiation cystitis found no significant differences in adverse events between patients receiving phenazopyridine and a matched comparator group 7.
- However, the use of phenazopyridine for extended periods of time is not well-studied, and more research is needed to fully understand the potential risks and benefits of long-term use 7.