Drug side effects
phenazopyridine Side Effects
The reactions most often reported to the FDA for phenazopyridine (also sold as Pyridium, AZO), with demographics, serious outcomes, and reporting trends.
Data updated 2026-05-15
- 3,599
- FAERS reports
Data from the FDA Adverse Event Reporting System (FAERS), 1992 to 2025. A FAERS report records a temporal association, not proof of cause. See our methodology for how figures are compiled and de-duplicated.
The most commonly reported side effects of phenazopyridine come from 3,599 reports to the FDA, broken down here by frequency, patient demographics, and serious outcomes.
This page analyzes 3,599 reports to the FDA Adverse Event Reporting System (FAERS) for phenazopyridine (Pyridium): the reactions reported most often, who reported them, serious outcomes such as hospitalization, and year-over-year trends. A FAERS report does not prove the drug caused the effect, and report volume tracks how widely a drug is used, not how likely an effect is for any one person. Educational information, not medical advice.
Total Reports
3,599
Reports Mentioning Death
261
7.3% of reports — not proof the medicine caused the death
Hospitalizations
1,205
33.5% of reports
Top Indication
Product Used For Unknown Indication
Most Reported Adverse Reactions
Who Reports Side Effects
Gender Distribution
Age Distribution
Reporting Trend by Year
Reactions in Death Reports
Top reactions reported in 261 reports where death was an outcome. These are voluntarily reported and do not establish causation.
| Reaction | Reports |
|---|---|
| DEATH | 98 |
| COMPLETED SUICIDE | 31 |
| ACUTE KIDNEY INJURY | 24 |
| NAUSEA | 24 |
| RENAL FAILURE | 24 |
| CHRONIC KIDNEY DISEASE | 23 |
| URINARY TRACT INFECTION | 18 |
| FATIGUE | 17 |
| VOMITING | 16 |
| PAIN | 14 |
| ASTHENIA | 13 |
| DIARRHOEA | 12 |
| DYSPNOEA | 12 |
| END STAGE RENAL DISEASE | 12 |
| MYOCARDIAL INFARCTION | 12 |
| PNEUMONIA | 12 |
| ABDOMINAL PAIN | 11 |
| ANAEMIA | 11 |
| ANXIETY | 11 |
Reactions in Hospitalization Reports
Top reactions in 1,205 reports where hospitalization was an outcome.
| Reaction | Reports |
|---|---|
| URINARY TRACT INFECTION | 139 |
| PAIN | 127 |
| NAUSEA | 123 |
| ACUTE KIDNEY INJURY | 104 |
| VOMITING | 95 |
| FATIGUE | 89 |
| DIARRHOEA | 86 |
| CHRONIC KIDNEY DISEASE | 85 |
| RENAL FAILURE | 82 |
| FALL | 76 |
| DYSPNOEA | 75 |
| HEADACHE | 68 |
| ANXIETY | 67 |
| ABDOMINAL PAIN | 65 |
| DIZZINESS | 63 |
| ANAEMIA | 61 |
| DEHYDRATION | 61 |
| DEPRESSION | 61 |
| PNEUMONIA | 61 |
| ASTHENIA | 59 |
Nearby, Related Medications
What the FAERS Data Reveals About phenazopyridine Side Effects
The FDA Adverse Event Reporting System (FAERS) contains 3,599 voluntary reports linked to phenazopyridine and its brand equivalents (Pyridium, AZO), spanning 1992 through 2025. Of those, 261 (7.3%) listed death as an outcome and 1,205 (33.5%) involved hospitalization. The most common indication reported alongside adverse events was Product Used For Unknown Indication.
Demographic breakdowns help contextualize who is being exposed to the drug. Of reports with known sex, 76% were female and 24% male; age distribution skews toward 45-64, with 852 reports in that bracket. The single most reported reaction is chronic kidney disease with 392 submissions, followed by nausea and pain.
How to read these numbers
FAERS is a signal-detection tool, not a scorecard. Reports are voluntary, and a single case may list multiple suspect drugs, so numbers above should not be read as incidence rates or per-patient risk. Widely prescribed drugs naturally accumulate more reports than niche therapies even when individual risk is low. These aggregates are useful for spotting patterns that merit further pharmacovigilance, not for choosing between medications. This page is for educational reference only and is not medical advice, speak with a licensed clinician about any side-effect concerns.
Drugs With a Similar FAERS Report Volume
Other medications with a total FDA adverse-event report count closest to phenazopyridine's 3,599.
Read our methodology - how this data is sourced, computed, and verified.