Fentanyl vs Hydromorphone: side effects in FDA adverse event reports
At a glance
| Fentanyl | Hydromorphone | |
|---|---|---|
| Drug class | Opioid Agonist | – |
| Brand names | Fentanyl System | Hydromorphone Hydrochloride |
| FAERS reports | 97,898 | 91,449 |
| Serious | 85% | 93% |
| Death outcome | 27,747 | 28,105 |
| Boxed warning | Yes SERIOUS AND LIFE-THREATENING RISKS FROM USE OF FENTANYL TRANSDERMAL SYSTEM . WARNING: SERIOUS AND LIFE-THREATENING RISKS FROM USE OF FENTANYL TRANSDERMAL SYSTEM | Yes SERIOUS AND LIFE-THREATENING RISKS FROM USE OF HYDROMORPHONE HYDROCHLORIDE WARNING: SERIOUS AND LIFE-THREATENING RISKS FROM USE OF HYDROMORPHONE HYDROCHLORIDE S |
Signals both drugs share
| Reaction | Fentanyl | Hydromorphone | Label screen (A / B) |
|---|---|---|---|
| Radiculopathy | 179 · PRR 15.5 | 265 · PRR 25.5 | Not in label — unassessed / Not in label — unassessed |
| Female genital tract fistula | 153 · PRR 20.8 | 242 · PRR 37.4 | Not in label — unassessed / Not in label — unassessed |
| Vaginal flatulence | 125 · PRR 148.5 | 224 · PRR 646.9 | Not in label — unassessed / Not in label — unassessed |
| Inspiratory capacity decreased | 99 · PRR 120.4 | 95 · PRR 120.9 | Not in label — unassessed / Not in label — unassessed |
| Hypermobility syndrome | 60 · PRR 29.4 | 41 · PRR 20.6 | Not in label — unassessed / Not in label — unassessed |
Labeled signals distinctive to Fentanyl
- Serotonin syndrome — n=1,318, PRR 15.8 Labeled adverse reaction
- Respiratory depression — n=920, PRR 17.3 Labeled — boxed warning
- Prescription drug used without a prescription — n=629, PRR 24.5 Labeled (related wording)
- Hyperthermia malignant — n=225, PRR 38.4 Labeled (related wording)
- Accidental death — n=148, PRR 18.5 Labeled (related wording)
- Intensive care unit acquired weakness — n=60, PRR 39.8 Labeled (related wording)
Labeled signals distinctive to Hydromorphone
- Drug withdrawal syndrome — n=14,329, PRR 44.1 Labeled (related wording)
- Drug withdrawal syndrome neonatal — n=2,771, PRR 52.1 Labeled (related wording)
- Substance use disorder — n=247, PRR 19.9 Labeled adverse reaction
- Vision abnormal neonatal — n=109, PRR 79.5 Labeled (related wording)
- Substance dependence — n=103, PRR 41.6 Labeled (related wording)
- Drug tolerance increased — n=75, PRR 24.1 Labeled (related wording)
- Medical device site pain — n=44, PRR 19.4 Labeled (related wording)
Common questions
Which has more reported side effects, Fentanyl or Hydromorphone?
Fentanyl has 97,898 FAERS reports and Hydromorphone 91,449. More reports does not mean more dangerous: volume follows how widely and how long a drug has been used, prescription vs over-the-counter status, and publicity. The seriousness share (85% vs 93%) is a better like-for-like signal of the kind of problems reported.
Which side effects do Fentanyl and Hydromorphone share?
Both drugs carry disproportionality signals for radiculopathy, female genital tract fistula, vaginal flatulence, inspiratory capacity decreased, hypermobility syndrome. Shared signals often reflect a shared drug class or the condition both are used for.
Is Fentanyl or Hydromorphone safer?
FAERS cannot answer that: it has no denominator and no comparator. Use this page to see which risks are already on each label and which signals are unlabeled, then check the prescribing information and your clinician for your situation.
Sources: openFDA FAERS pair statistics (OpenPV build 2026-09-14), FDA labels via openFDA, openFDA count queries for seriousness and deaths. Pair chosen because it is a commonly searched comparison. Generated 2026-10-08.