Drug · FAERS side-effect profile with label screen
Phenazopyridine side effects: what 3,716 FDA adverse event reports show
Drug class
Lack of evidence
FDA label, Indications wording
Brand names
Phenazopyridine Hydrochloride
openFDA label
Who reports
3,716 reports · 70% serious · 265 with death outcome · 75% female
openFDA FAERS counts, all years, deduplication not applied
Used for
Phenazopyridine HCl is indicated for the symptomatic relief of pain, burning, urgency, frequency, and other discomforts arising from irritation of the lower urinary tract mucosa caused by infection, trauma, surgery, endoscopic procedures, or the passage of sounds or catheters. The use of Phenazopyridine HCl for relief of symptoms should not delay definitive diagnosis and treatment of causative conditions.
FDA label, Indications and Usage
What it is
DESCRIPTION Phenazopyridine Hydrochloride, USP is light or dark red to dark violet, odorless, slightly bitter, crystalline powder. It has a specific local analgesic effect in the urinary tract, promptly relieving burning and pain. It has the following structural formula: C 11 H 11 N 5 •HCl M.W.
FDA label, Description section
Boxed warning
None in the current label
How to read this page. FAERS is a spontaneous-reporting system: counts are not incidence rates and a signal is not proof of causation.
Each reaction below is run through an automated screen — is the term in the FDA label (known), in the indications (the disease being treated), an administrative/coding term, or none of these (unlabeled)?
That screen is mechanical text matching, not a causality assessment. The 30 hand-written Bradford Hill assessments are on the causality assessment page. Not medical advice.
Causality screen of the 40 strongest signals
Reporting / coding artifact 1Lab value / disease marker 1No label text to screen 38
What the badges mean
- Reporting / coding artifact An administrative, monitoring or exposure term (product issue, off-label use, 'test normal', overdose...). Not a biological reaction; a high PRR here reflects how reports are coded.
- Lab value / disease marker A laboratory result, investigation or disease-activity marker (antibody positive, CRP abnormal, swollen joint count) not described in the label. These usually mirror the monitored disease or testing protocol rather than a drug effect; not screened further.
- Not in label — unassessed Not found in the label text, not an artifact pattern. This is a genuine candidate for a formal causality assessment (Bradford Hill / WHO-UMC); it has NOT had one here.
- No label text to screen No validated FDA label was retrievable for this product, so the screen could not run. Disproportionality only.
Strongest disproportionality signals
Flagged terms (PRR ≥ 2, χ² ≥ 4, n ≥ 10), ranked by PRR; infinite PRRs (no comparator reports) excluded. The EBGM column is a second, shrinkage-based estimate (MGPS) with its 5th percentile EB05 and the BCPNN IC025; a pair flagged by PRR alone is marked PRR-only and should be read as fragile. The strata column recomputes the PRR on serious reports only and flags pairs whose reports are unusually skewed by sex or come mostly from consumers rather than clinicians. 275 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
Show:
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Chronic kidney disease | 393 | 29.1 26.5–31.9ROR 32.4 · χ² 10,601 / p <1e-300 | 28.9 EB05 26.6 · IC025 +4.6 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 24.2 | no trial data cached |
| End stage renal disease | 93 | 28.6 23.4–35.0ROR 29.3 · χ² 2,440 / p <1e-300 | 28.3 EB05 23.8 · IC025 +4.3 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 23.4 | no trial data cached |
| Dysuria (painful urination) | 100 | 15.3 12.6–18.6ROR 15.7 · χ² 1,325 / p 2e-290 | 15.2 EB05 12.9 · IC025 +3.5 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 13.8 · ♀ 55% (drug 75%) | no trial data cached |
| Tubulointerstitial nephritis | 50 | 15.1 11.5–19.9ROR 15.3 · χ² 643 / p 5e-142 | 14.9 EB05 11.7 · IC025 +3.3 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 12.4 | no trial data cached |
| Flank pain | 22 | 13.3 8.8–20.2ROR 13.4 · χ² 237 / p 8e-54 | 12.6 EB05 8.4 · IC025 +2.7 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 14.3 | no trial data cached |
| Cystitis | 75 | 13.3 10.6–16.6ROR 13.5 · χ² 837 / p 2e-184 | 13.1 EB05 10.7 · IC025 +3.2 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 11.7 | no trial data cached |
| Micturition urgency | 25 | 12.5 8.4–18.4ROR 12.5 · χ² 252 / p 6e-57 | 11.8 EB05 8.1 · IC025 +2.7 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 12.2 | no trial data cached |
| Impaired gastric emptying | 28 | 12.4 8.6–17.9ROR 12.5 · χ² 282 / p 1e-63 | 11.8 EB05 8.3 · IC025 +2.7 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 11.5 | no trial data cached |
| Bladder disorder | 21 | 11.9 7.8–18.3ROR 12.0 · χ² 199 / p 2e-45 | 11.1 EB05 7.2 · IC025 +2.5 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious n=16 · ♀ 33% (drug 75%) | no trial data cached |
| Renal injury | 63 | 11.9 9.3–15.1ROR 12.0 · χ² 615 / p 5e-136 | 11.6 EB05 9.3 · IC025 +3.0 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 9.8 | no trial data cached |
| Renal tubular necrosis | 19 | 10.9 7.0–17.1ROR 11.0 · χ² 161 / p 3e-37 | 9.9 EB05 6.3 · IC025 +2.3 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 9.0 | no trial data cached |
| Renal failure (kidney failure) | 253 | 10.7 9.5–12.0ROR 11.4 · χ² 2,220 / p <1e-300 | 10.6 EB05 9.5 · IC025 +3.2 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 8.8 | no trial data cached |
| Anhedonia | 50 | 10.7 8.1–14.0ROR 10.8 · χ² 428 / p 2e-95 | 10.3 EB05 8.0 · IC025 +2.8 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 9.7 · 76% consumer | no trial data cached |
| Acute kidney injury (sudden kidney damage) | 268 | 9.9 8.9–11.2ROR 10.6 · χ² 2,157 / p <1e-300 | 9.9 EB05 8.9 · IC025 +3.1 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 8.2 | no trial data cached |
| Urinary tract infection (bladder infection) | 289 | 9.6 8.6–10.7ROR 10.3 · χ² 2,231 / p <1e-300 | 9.5 EB05 8.6 · IC025 +3.0 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 8.1 | no trial data cached |
| Nephrolithiasis (kidney stones) | 75 | 9.3 7.4–11.6ROR 9.4 · χ² 545 / p 1e-120 | 9.0 EB05 7.3 · IC025 +2.7 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 8.2 | no trial data cached |
| Osteopenia | 25 | 9.3 6.3–13.7ROR 9.3 · χ² 176 / p 2e-40 | 8.4 EB05 5.8 · IC025 +2.3 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 9.0 | no trial data cached |
| Urinary retention | 52 | 8.8 6.7–11.6ROR 8.9 · χ² 353 / p 5e-79 | 8.4 EB05 6.6 · IC025 +2.6 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 7.5 · ♀ 44% (drug 75%) | no trial data cached |
| Economic problem | 24 | 8.8 5.9–13.1ROR 8.8 · χ² 158 / p 2e-36 | 7.9 EB05 5.5 · IC025 +2.2 3/3 methods agree | Reporting / coding artifact | serious PRR 7.9 | no trial data cached |
| Vitamin d deficiency | 14 | 8.1 4.8–13.7ROR 8.1 · χ² 80 / p 2e-19 | 6.7 EB05 4.2 · IC025 +1.8 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 7.5 | no trial data cached |
| Nephropathy | 13 | 7.8 4.5–13.5ROR 7.8 · χ² 71 / p 2e-17 | 6.4 EB05 3.9 · IC025 +1.7 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 6.9 | no trial data cached |
| Kidney infection | 27 | 7.8 5.3–11.3ROR 7.8 · χ² 153 / p 2e-35 | 7.0 EB05 5.0 · IC025 +2.1 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 7.2 · 74% consumer | no trial data cached |
| Chromaturia | 30 | 7.5 5.2–10.7ROR 7.5 · χ² 162 / p 2e-37 | 6.9 EB05 5.0 · IC025 +2.1 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 6.5 · ♀ 55% (drug 75%) · 77% consumer | no trial data cached |
| Incontinence | 14 | 7.5 4.4–12.6ROR 7.5 · χ² 72 / p 1e-17 | 6.2 EB05 3.9 · IC025 +1.7 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 5.9 | no trial data cached |
| Intervertebral disc degeneration | 12 | 7.3 4.1–12.8ROR 7.3 · χ² 59 / p 9e-15 | 5.9 EB05 3.5 · IC025 +1.6 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 6.9 | no trial data cached |
| Tooth fracture | 14 | 7.2 4.2–12.1ROR 7.2 · χ² 68 / p 7e-17 | 6.0 EB05 3.7 · IC025 +1.7 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 8.3 | no trial data cached |
| Dental caries | 14 | 7.2 4.2–12.1ROR 7.2 · χ² 68 / p 8e-17 | 6.0 EB05 3.7 · IC025 +1.7 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 7.8 | no trial data cached |
| Mental status changes | 35 | 7.1 5.1–9.9ROR 7.2 · χ² 178 / p 8e-41 | 6.6 EB05 4.9 · IC025 +2.1 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 6.5 · ♀ 48% (drug 75%) | no trial data cached |
| Osteoporosis | 50 | 6.9 5.2–9.0ROR 6.9 · χ² 244 / p 2e-55 | 6.5 EB05 5.1 · IC025 +2.2 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 6.4 | no trial data cached |
| Urosepsis | 11 | 6.7 3.7–12.2ROR 6.8 · χ² 48 / p 2e-12 | 5.4 EB05 3.2 · IC025 +1.4 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 5.6 | no trial data cached |
| Injury | 84 | 6.7 5.4–8.3ROR 6.8 · χ² 403 / p 5e-90 | 6.5 EB05 5.4 · IC025 +2.3 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 6.9 | no trial data cached |
| Pollakiuria (frequent urination) | 49 | 6.6 5.0–8.8ROR 6.7 · χ² 229 / p 4e-52 | 6.3 EB05 4.9 · IC025 +2.2 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 8.0 | no trial data cached |
| Macular degeneration | 14 | 6.6 3.9–11.2ROR 6.7 · χ² 61 / p 2e-15 | 5.6 EB05 3.5 · IC025 +1.6 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 5.9 | no trial data cached |
| Blood urine present | 22 | 6.5 4.3–9.9ROR 6.5 · χ² 97 / p 3e-23 | 5.8 EB05 4.0 · IC025 +1.8 3/3 methods agree | Lab value / disease marker | serious PRR 6.6 · ♀ 38% (drug 75%) | no trial data cached |
| Urinary incontinence | 34 | 6.5 4.6–9.1ROR 6.5 · χ² 152 / p 3e-35 | 6.0 EB05 4.5 · IC025 +2.0 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 6.1 | no trial data cached |
| Nerve injury | 12 | 6.1 3.5–10.7ROR 6.1 · χ² 46 / p 6e-12 | 5.0 EB05 3.1 · IC025 +1.4 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 5.9 | no trial data cached |
| Nocturia (night-time urination) | 13 | 6.1 3.5–10.4ROR 6.1 · χ² 50 / p 8e-13 | 5.1 EB05 3.2 · IC025 +1.4 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 6.6 | no trial data cached |
| Gastrooesophageal reflux disease (acid reflux) | 85 | 6.0 4.8–7.4ROR 6.1 · χ² 349 / p 4e-78 | 5.8 EB05 4.8 · IC025 +2.2 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 7.0 | no trial data cached |
| Pelvic pain | 19 | 5.9 3.8–9.2ROR 5.9 · χ² 72 / p 9e-18 | 5.2 EB05 3.5 · IC025 +1.6 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 5.6 | no trial data cached |
| Dizziness postural | 10 | 5.9 3.2–10.9ROR 5.9 · χ² 36 / p 1e-9 | 4.7 EB05 2.8 · IC025 +1.2 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious n=9 | no trial data cached |
Trial evidence (ClinicalTrials.gov)
Trial cross-check not yet run for this drug (ClinicalTrials.gov pull covers the 800 most-reported drugs first).
Most frequently reported reactions
By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Chronic kidney disease | 393 | 29.1 26.5–31.9ROR 32.4 · χ² 10,601 / p <1e-300 | 28.9 EB05 26.6 · IC025 +4.6 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 24.2 | no trial data cached |
| Pain | 299 | 2.7 2.5–3.1ROR 2.9 · χ² 339 / p 6e-76 | 2.7 EB05 2.5 · IC025 +1.3 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 3.0 | no trial data cached |
| Urinary tract infection (bladder infection) | 289 | 9.6 8.6–10.7ROR 10.3 · χ² 2,231 / p <1e-300 | 9.5 EB05 8.6 · IC025 +3.0 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 8.1 | no trial data cached |
| Acute kidney injury (sudden kidney damage) | 268 | 9.9 8.9–11.2ROR 10.6 · χ² 2,157 / p <1e-300 | 9.9 EB05 8.9 · IC025 +3.1 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 8.2 | no trial data cached |
| Renal failure (kidney failure) | 253 | 10.7 9.5–12.0ROR 11.4 · χ² 2,220 / p <1e-300 | 10.6 EB05 9.5 · IC025 +3.2 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 8.8 | no trial data cached |
| Anxiety | 188 | 3.7 3.2–4.3ROR 3.9 · χ² 376 / p 6e-84 | 3.7 EB05 3.3 · IC025 +1.6 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 4.1 | no trial data cached |
| Drug hypersensitivity | 143 | 4.2 3.5–4.9ROR 4.3 · χ² 342 / p 1e-76 | 4.1 EB05 3.6 · IC025 +1.8 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 3.1 | no trial data cached |
| Depression | 141 | 3.5 3.0–4.1ROR 3.6 · χ² 249 / p 2e-56 | 3.4 EB05 3.0 · IC025 +1.5 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 3.6 | no trial data cached |
| Constipation | 124 | 3.2 2.7–3.8ROR 3.3 · χ² 191 / p 1e-43 | 3.2 EB05 2.8 · IC025 +1.4 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 3.4 | no trial data cached |
| Emotional distress | 100 | 4.6 3.8–5.6ROR 4.7 · χ² 284 / p 6e-64 | 4.5 EB05 3.8 · IC025 +1.9 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 4.3 | no trial data cached |
| Dysuria (painful urination) | 100 | 15.3 12.6–18.6ROR 15.7 · χ² 1,325 / p 2e-290 | 15.2 EB05 12.9 · IC025 +3.5 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 13.8 · ♀ 55% (drug 75%) | no trial data cached |
| Muscle spasms | 97 | 3.0 2.4–3.6ROR 3.0 · χ² 127 / p 1e-29 | 2.9 EB05 2.5 · IC025 +1.2 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 2.9 | no trial data cached |
| End stage renal disease | 93 | 28.6 23.4–35.0ROR 29.3 · χ² 2,440 / p <1e-300 | 28.3 EB05 23.8 · IC025 +4.3 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 23.4 | no trial data cached |
| Gastrooesophageal reflux disease (acid reflux) | 85 | 6.0 4.8–7.4ROR 6.1 · χ² 349 / p 4e-78 | 5.8 EB05 4.8 · IC025 +2.2 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 7.0 | no trial data cached |
| Injury | 84 | 6.7 5.4–8.3ROR 6.8 · χ² 403 / p 5e-90 | 6.5 EB05 5.4 · IC025 +2.3 3/3 methods agree | No label text to screen label has no adverse-reaction text | serious PRR 6.9 | no trial data cached |
Unlabeled candidate signals
Every screened signal with n ≥ 20 was either labeled, an indication term, or an artifact pattern — no unlabeled candidate stood out in the top signals.
Want to assess one of these properly? The runbook describes the Bradford Hill / trial-evidence workflow used on the assessment page, and handoff_top1000_signals.csv lists the strongest unassessed pairs across all drugs.
Common questions
What are the most reported side effects of Phenazopyridine?
In FDA FAERS, the most frequently co-reported reaction terms for Phenazopyridine are chronic kidney disease, pain, urinary tract infection, acute kidney injury, renal failure, anxiety. These are report counts, not rates: FAERS has no denominator, reporting is voluntary and uneven, and a term can be reported because of the illness being treated rather than the drug.
Does Phenazopyridine have an FDA boxed warning?
No. The FDA label retrieved for Phenazopyridine has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Phenazopyridine causes these side effects?
No. A disproportionality signal (PRR, ROR) means a reaction is reported more often with this drug than with others in the database. That can reflect a real effect, but also the disease being treated, stimulated reporting after news or litigation, co-medications, or how reports are coded. Causality needs temporality, dose-response, biological plausibility, consistency across data sources and, ideally, trial or cohort evidence. This page screens each term against the FDA label and ClinicalTrials.gov results; it does not establish causation.
Sources & methods
- FDA label via openFDA (set ID 132cc592-6b03-4b75-bf39-df476fb9dc81, effective 20260814; matched on
openfda.generic_name.exact:"PHENAZOPYRIDINE" AND openfda.product_type:"HUMAN PRESCRIPTION DRUG") - Bayesian shrinkage measures computed offline over all 1,317,300 cached pairs: BCPNN information component (IC, with Norén closed-form IC025) and MGPS empirical-Bayes geometric mean (EBGM, EB05) with a two-component gamma prior fitted by maximum marginal likelihood (α₁=0.57, β₁=0.02, α₂=1.42, β₂=0.70, w=0.17); unstratified
- FAERS pair statistics from the OpenPV build of 2026-09-14 (openFDA
count=aggregation, fieldpatient.drug.openfda.generic_name.exact, 315 reaction terms, min 3 co-reports); PRR/ROR with 95% CI, chi-square with Yates correction - Serious-only and stratified counts (serious:1, patient.patientsex, primarysource.qualification) from openFDA count queries; serious-only PRR uses the drug serious report total and the term global serious total (N_serious=11,882,979); strata shown only when n ≥ 20
- Seriousness and sex counts from openFDA
count=serious,patient.patientsex,seriousnessdeath
Page generated 2026-10-08. Label and PubChem text are retrieved automatically and may lag the current label; always check the current prescribing information. OpenPV is a beta research tool of the Open Source Medicine Foundation.