Lamotrigine vs Topiramate: side effects in FDA adverse event reports
At a glance
| Lamotrigine | Topiramate | |
|---|---|---|
| Drug class | Anti-epileptic Agent, Mood Stabilizer | – |
| Brand names | – | – |
| FAERS reports | 130,963 | 91,049 |
| Serious | 72% | 69% |
| Death outcome | 11,279 | 6,839 |
| Boxed warning | Yes SERIOUS SKIN RASHES Lamotrigine can cause serious rashes requiring hospitalization and discontinuation of treatment. The incidence of these rashes, which have i | No |
Signals both drugs share
| Reaction | Lamotrigine | Topiramate | Label screen (A / B) |
|---|---|---|---|
| Duodenal ulcer perforation | 824 · PRR 20.1 | 646 · PRR 21.8 | Labeled (related wording) / Not in label — unassessed |
| Peripheral venous disease | 638 · PRR 30.3 | 620 · PRR 41.5 | Labeled (related wording) / Labeled (related wording) |
| Complex partial seizures | 173 · PRR 28.9 | 99 · PRR 21.7 | Labeled (related wording) / Labeled (related wording) |
| Change in seizure presentation | 86 · PRR 24.0 | 71 · PRR 27.4 | Labeled (related wording) / Likely indication confounding |
| Blepharospasm | 936 · PRR 28.3 | 828 · PRR 34.8 | Not in label — unassessed / Not in label — unassessed |
| Breast cancer stage iii | 810 · PRR 22.9 | 659 · PRR 25.7 | Not in label — unassessed / Not in label — unassessed |
| Facet joint syndrome | 744 · PRR 49.3 | 622 · PRR 55.5 | Not in label — unassessed / Not in label — unassessed |
| Onychomadesis | 647 · PRR 29.4 | 565 · PRR 35.5 | Not in label — unassessed / Not in label — unassessed |
| Rheumatic fever | 509 · PRR 21.0 | 524 · PRR 30.8 | Not in label — unassessed / Not in label — unassessed |
| Onychomycosis | 456 · PRR 18.5 | 400 · PRR 22.7 | Not in label — unassessed / Not in label — unassessed |
| Myoclonic epilepsy | 210 · PRR 26.5 | 175 · PRR 30.4 | Likely indication confounding / Likely indication confounding |
| Overlap syndrome | 122 · PRR 34.3 | 94 · PRR 35.6 | Not in label — unassessed / Not in label — unassessed |
| Atonic seizures | 114 · PRR 26.6 | 74 · PRR 23.1 | Likely indication confounding / Likely indication confounding |
| Hypocholesterolaemia | 88 · PRR 64.0 | 96 · PRR 102.6 | Not in label — unassessed / Not in label — unassessed |
Labeled signals distinctive to Lamotrigine
- Epilepsy — n=3,415, PRR 20.1 Labeled — boxed warning
- Stevens-johnson syndrome — n=2,615, PRR 21.2 Labeled — boxed warning
- Petit mal epilepsy — n=696, PRR 25.3 Labeled (related wording)
- Seizure cluster — n=92, PRR 20.6 Labeled adverse reaction
- Simple partial seizures — n=82, PRR 17.8 Labeled (related wording)
- Partial seizures with secondary generalisation — n=81, PRR 33.3 Labeled (related wording)
Labeled signals distinctive to Topiramate
- Angle closure glaucoma — n=597, PRR 68.7 Labeled adverse reaction
- Myopia — n=303, PRR 33.1 Labeled adverse reaction
- Choroidal effusion — n=198, PRR 74.5 Labeled (related wording)
- Medication overuse headache — n=130, PRR 40.5 Labeled (related wording)
- Cleft lip and palate — n=127, PRR 28.6 Labeled (related wording)
- Cleft lip — n=106, PRR 30.7 Labeled adverse reaction
- Acute myopia — n=62, PRR 128.8 Labeled adverse reaction
- Choroidal detachment — n=62, PRR 28.4 Labeled adverse reaction
Common questions
Which has more reported side effects, Lamotrigine or Topiramate?
Lamotrigine has 130,963 FAERS reports and Topiramate 91,049. 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 (72% vs 69%) is a better like-for-like signal of the kind of problems reported.
Which side effects do Lamotrigine and Topiramate share?
Both drugs carry disproportionality signals for duodenal ulcer perforation, peripheral venous disease, complex partial seizures, change in seizure presentation, blepharospasm. Shared signals often reflect a shared drug class or the condition both are used for.
Is Lamotrigine or Topiramate 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.