Diphenhydramine vs Dimenhydrinate: side effects in FDA adverse event reports
At a glance
| Diphenhydramine | Dimenhydrinate | |
|---|---|---|
| Drug class | – | – |
| Brand names | Nightime Sleep Aid | – |
| FAERS reports | 164,753 | 10,594 |
| Serious | 71% | 95% |
| Death outcome | 22,785 | 835 |
| Boxed warning | No | No |
Signals both drugs share
| Reaction | Diphenhydramine | Dimenhydrinate | Label screen (A / B) |
|---|---|---|---|
| Enthesopathy | 205 · PRR 18.9 | 199 · PRR 286.1 | No label text to screen / Not in label — unassessed |
| Neurologic neglect syndrome | 172 · PRR 56.2 | 172 · PRR 881.3 | No label text to screen / Not in label — unassessed |
| Carotid artery thrombosis | 171 · PRR 31.7 | 172 · PRR 500.4 | No label text to screen / Not in label — unassessed |
| Adjustment disorder | 176 · PRR 19.7 | 165 · PRR 286.8 | No label text to screen / Not in label — unassessed |
Labeled signals distinctive to Diphenhydramine
- None stood out among the strongest labeled signals.
Labeled signals distinctive to Dimenhydrinate
- None stood out among the strongest labeled signals.
Common questions
Which has more reported side effects, Diphenhydramine or Dimenhydrinate?
Diphenhydramine has 164,753 FAERS reports and Dimenhydrinate 10,594. 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 (71% vs 95%) is a better like-for-like signal of the kind of problems reported.
Which side effects do Diphenhydramine and Dimenhydrinate share?
Both drugs carry disproportionality signals for enthesopathy, neurologic neglect syndrome, carotid artery thrombosis, adjustment disorder. Shared signals often reflect a shared drug class or the condition both are used for.
Is Diphenhydramine or Dimenhydrinate 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.