What is Pyridium (Phenazopyridine)?
Pyridium (phenazopyridine hydrochloride) is an over-the-counter urinary tract analgesic that provides direct symptomatic relief of dysuria, burning, urgency, frequency, and suprapubic discomfort associated with lower urinary tract irritation and infections. 1, 2
Mechanism of Action
- Phenazopyridine is rapidly excreted by the kidneys (up to 66% of an oral dose excreted unchanged in urine) where it exerts a topical analgesic effect directly on the mucosa of the urinary tract 3
- The precise mechanism of action is not fully understood, but it provides local pain relief at the site of urinary tract irritation 3
Clinical Indications
- The American Urological Association recommends phenazopyridine as an over-the-counter option for symptom management during flare-ups of interstitial cystitis/bladder pain syndrome 2
- It is commonly used for symptomatic relief in patients with acute uncomplicated cystitis and urinary tract infections 1, 2
- Phenazopyridine provides symptomatic relief only—it does not treat the underlying infection and should be used in conjunction with appropriate antibiotic therapy when infection is present 4, 5
Dosing and Duration
- Available in over-the-counter formulations at lower doses compared to prescription-strength products 1
- Typical dosing is 200 mg orally 2-3 times daily 4, 5
- Should be used for short-term symptomatic relief only, typically 2-3 days maximum 1
- The American Urological Association recommends seeking medical care if symptoms persist beyond 2 days 1
Important Patient Counseling Points
- Patients must be counseled that urine will turn orange/red, which is expected and harmless 1
- This discoloration can also affect tears, sweat, and other body fluids 6
Significant Adverse Effects and Contraindications
Common Side Effects
- Gastrointestinal upset (nausea) occurs rarely, reported in approximately 1.3% of patients 5
- Orange/red discoloration of urine is universal and expected 1
Serious Adverse Effects (Rare but Important)
- Methemoglobinemia can occur, particularly with doses and duration exceeding manufacturer specifications 7
- Acute interstitial nephritis has been reported even with therapeutic doses 8
- Hepatitis and acute renal failure are rare complications 8
- Phenazopyridine may accelerate stone growth if urinary calculi are already present 9
Critical Safety Consideration
- In patients taking serotonergic medications (MAOIs, SSRIs, SNRIs, TCAs), if methemoglobinemia develops, vitamin C should be used instead of methylene blue to avoid risk of serotonin syndrome 7
Clinical Efficacy
- In a randomized, placebo-controlled trial, 100% of patients taking phenazopyridine had improvement after 6 hours, with 43.3% reporting "significant improvement" compared to placebo 4
- Pain severity decreased by 57.4% versus 35.9% with placebo, and general discomfort decreased by 53.4% versus 28.8% with placebo after 6 hours 4
- When combined with fosfomycin for acute cystitis, phenazopyridine provided superior pain relief compared to fosfomycin plus drotaverine, with complete pain resolution in 48 hours 5