HIGH-VOLUME · HOSP-HEAVY
allopurinol Side Effects
allopurinol (also sold as Zyloprim) is HIGH-VOLUME in this FAERS book #44 of 524 by FAERS report count. Signature opener: HOSP-HEAVY - 49.2% mention hospitalization (74,277 reports).
Data updated 2026-05-15
- 150,998
- FAERS reports
FAERS voluntary reports, 1997 to 2025. High volume tracks exposure and reporting culture; see methodology for de-dup rules.
allopurinol: 49.2% mention hospitalization (74,277 reports). Death stamp DEATH-HEAVY; volume band HIGH-VOLUME #44 of 524 by FAERS report count.
High-report extract for allopurinol (Zyloprim): 150,998 FAERS rows (1997-2025). Top named reactions: DIARRHOEA, FATIGUE, DYSPNOEA. Outcome stamps DEATH-HEAVY · HOSP-HEAVY · SEX-BALANCED. FAERS is voluntary signal detection, not incidence.
Counts from the openFDA FAERS extract (1997–2025). Stamps MEGA-CASE · DEATH-HEAVY · HOSP-HEAVY · SEX-BALANCED.
DIARRHOEA leads 8,423 of 150,998 reports
Who reports · age peak 75+ (SEX-BALANCED)
Sex coding · SEX-BALANCED
Age peak 75+ (38,718 reports)
FAERS filings rising toward 2025
Reactions in Death Reports
Death-mentioned subset is HEAVY here (21,323 reports, 14.1%). Top co-reported reactions in that subset - voluntary, not causal.
| Reaction | Reports |
|---|---|
| DEATH | 6,649 |
| PNEUMONIA | 1,639 |
| SEPSIS | 1,505 |
| DYSPNOEA | 1,204 |
| RENAL FAILURE | 1,204 |
| PYREXIA | 1,042 |
| ACUTE KIDNEY INJURY | 1,029 |
| ANAEMIA | 1,002 |
| GENERAL PHYSICAL HEALTH DETERIORATION | 976 |
| DIARRHOEA | 949 |
| NAUSEA | 893 |
| CARDIAC ARREST | 842 |
| MULTIPLE ORGAN DYSFUNCTION SYNDROME | 825 |
| ASTHENIA | 811 |
| RESPIRATORY FAILURE | 804 |
| HYPOTENSION | 787 |
| THROMBOCYTOPENIA | 748 |
| FATIGUE | 743 |
| VOMITING | 727 |
Reactions in Hospitalization Reports
Hospitalization is HEAVY (74,277, 49.2% of the book). Top reactions in those rows:
| Reaction | Reports |
|---|---|
| DYSPNOEA | 4,959 |
| PNEUMONIA | 4,591 |
| ACUTE KIDNEY INJURY | 4,575 |
| PYREXIA | 4,538 |
| DIARRHOEA | 4,154 |
| ANAEMIA | 3,921 |
| NAUSEA | 3,461 |
| FATIGUE | 3,365 |
| ASTHENIA | 3,265 |
| FALL | 3,173 |
| HYPOTENSION | 3,021 |
| VOMITING | 2,774 |
| FEBRILE NEUTROPENIA | 2,694 |
| RENAL FAILURE | 2,572 |
| DIZZINESS | 2,450 |
| GENERAL PHYSICAL HEALTH DETERIORATION | 2,367 |
| SEPSIS | 2,367 |
| DEHYDRATION | 2,279 |
| ATRIAL FIBRILLATION | 2,164 |
How to read allopurinol FAERS figures (MEGA-CASE · DEATH-HEAVY · HOSP-HEAVY)
FAERS holds 150,998 voluntary reports linked to allopurinol (Zyloprim), 1997-2025. Death is listed on 21,323 (14.1%). Hospitalization appears on 74,277 (49.2%). Top co-reported indication: Product Used For Unknown Indication.
MEGA-CASE books overweight common drugs and loud reporting cultures; HOSP-HEAVY is the page opener, not a per-patient risk.
Read with allopurinol
Peers ranked by ABS(total_reports), then an ABS(death_share) pole; guide hop follows DEATH-HEAVY · HOSP-HEAVY stamps.
ABS(total_reports) peer at 155,068 FAERS cases (Δ 4,070 heavier vs allopurinol); DEATH-MARKED · HOSP-LIGHT · SEX-BALANCED vs this page's MEGA-CASE · DEATH-HEAVY · HOSP-HEAVY · SEX-BALANCED.
ABS(total_reports) peer at 155,147 FAERS cases (Δ 4,149 heavier vs allopurinol); DEATH-HEAVY · HOSP-MID · SEX-BALANCED vs this page's MEGA-CASE · DEATH-HEAVY · HOSP-HEAVY · SEX-BALANCED.
ABS(total_reports) peer at 157,236 FAERS cases (Δ 6,238 heavier vs allopurinol); DEATH-MARKED · HOSP-MID · SEX-BALANCED vs this page's MEGA-CASE · DEATH-HEAVY · HOSP-HEAVY · SEX-BALANCED.
ABS(total_reports) peer at 143,174 FAERS cases (Δ 7,824 lighter vs allopurinol); DEATH-MARKED · HOSP-LIGHT · SEX-BALANCED vs this page's MEGA-CASE · DEATH-HEAVY · HOSP-HEAVY · SEX-BALANCED.
ABS(death_share) pole at 62.1% death-mentioned reports (Δ 48.0 pp vs allopurinol's DEATH-HEAVY): CASELOAD · HOSP-MID.
allopurinol stamps DEATH-HEAVY · HOSP-HEAVY; FAERS outcome shares are signal-detection rates, not incidence. Read them next to caseload MEGA-CASE and the label guide.