Lamotrigine and Stevens-Johnson Syndrome: Warning Signs
Short answer: Lamotrigine (Lamictal) can cause rare, life-threatening skin reactions, including Stevens-Johnson syndrome and toxic epidermal necrolysis. Because a harmless rash cannot always be distinguished early from a serious one, a new rash requires prompt medical advice.
Reviewed and updated July 24, 2026.
What the boxed warning says
The FDA-approved Lamictal label warns that lamotrigine has caused serious rashes, including Stevens-Johnson syndrome, toxic epidermal necrolysis, and rash-related death. The overall risk is higher in children than adults, but serious reactions can occur at any age.
The label identifies several factors that may increase risk: taking valproate at the same time, exceeding the recommended starting dose, and increasing the dose faster than recommended. Cases have also occurred without those factors.
When does the risk occur?
Most life-threatening rashes reported with lamotrigine occur within two to eight weeks after starting treatment. Later cases have occurred, so time alone cannot rule out a serious reaction. Restarting after an interruption may also require a new titration plan; do not resume an old dose without the prescriber.
Warning signs that need urgent assessment
- A new or rapidly spreading rash
- Blisters, peeling skin, or painful skin
- Sores in the mouth, eyes, nose, or genital area
- Facial swelling
- Fever, marked fatigue, swollen lymph nodes, or flu-like symptoms with a rash
- Eye pain, redness, or light sensitivity
- Trouble breathing or other signs of a severe allergic reaction
Call emergency services for breathing difficulty, fainting, extensive blistering or peeling, or rapidly worsening symptoms. Otherwise contact the prescriber immediately for a new rash. Do not rely on a photograph or online checklist to rule out SJS.
Why early rashes are difficult to classify
Lamotrigine can also cause benign rashes. Unfortunately, the appearance at the beginning may not reliably predict which eruption will become serious. The label therefore advises discontinuation at the first sign of rash unless the rash is clearly not drug-related. That decision should be made urgently with a clinician because uncontrolled seizures or mood symptoms also carry risks.
Do not self-rechallenge
Do not restart lamotrigine after a rash unless a qualified prescriber has reviewed the reaction and decides the potential benefit justifies the risk. Re-exposure can cause a faster or more severe response. Tell every clinician and pharmacist about a prior suspected serious drug rash.
Other conditions that can resemble or accompany a rash
Serious lamotrigine reactions may include drug reaction with eosinophilia and systemic symptoms (DRESS), blood abnormalities, liver inflammation, or multiorgan hypersensitivity. Infection and other medicines can also cause rashes. Evaluation may require a medication timeline, examination, blood tests, and specialist input.
Safer use principles
- Follow the exact starting and escalation schedule.
- Make sure every prescriber knows about valproate and other medicines.
- Ask what to do if multiple doses are missed.
- Keep the Medication Guide and know how to reach the prescriber after hours.
- Seek advice promptly rather than waiting for a rash to become severe.
Primary sources
See the FDA-approved Lamictal prescribing information for the boxed warning, dosing schedules, contraindications, and complete safety information.
- DailyMed: current lamotrigine boxed warning and prescribing information
- MedlinePlus: lamotrigine patient information
This article is general information. Do not start, stop, restart, or change lamotrigine without prompt guidance from the prescribing clinician.
For additional evidence-based medication-risk analysis, browse the Science archive.
Related reading: For related context, read Ninth Circuit Open-Carry Decisions: What They Mean, Pink Cocaine (Tusi): What It Contains and Why It Is Risky, California’s Age-Appropriate Design Code Act Decision.
