Lamictal rash is the most common side effect of the anti-seizure drug Lamictal, which contains a medicine known as lamotrigine. The rash. Summer Heat and Sun Risks for. Antipsychotic. Medication. Users. State of New Jersey. Division of Mental Health and. Addiction Services. PREVENTION OF. Lamotrigine is used alone or together with other medicines to help . in a closed container at room temperature, away from heat, moisture, and direct light. fever, chills, headache, nausea, vomiting, rash, or sensitivity to light. Disclaimer: Our goal is to provide you with the most relevant and current information. Jeat reaction to medication always warrants read article call to the doctor. Important considerations for taking lamotrigine. Lamictal dosage information in more detail. This information is not a substitute for medical advice. Your mood or behavior may get worse. About About Drugs.