Lamotrigine should be started at a low dosage and titrated slowly to minimize the risk of Stevens-Johnson syndrome. If you start it at a high dose without titrated, it can cause Steven Johnson’s syndrome.
“Lamotrigine is an anti-epileptic medication that is often used in bipolar disorder. It can cause Stevens-Johnson syndrome, which is a severe disorder of the skin and mucous membranes. This most commonly occurs in children or when the drug is initiated at a high dosage, and is also more likely to occur in patients taking divalproex. To decrease the risk of Stevens-Johnson syndrome, it is recommended that lamotrigine therapy be started at a dosage of 25 mg daily and titrated every 2 weeks until the goal dosage is reached.
Ref: Brenner CJ, Shyn SI: Diagnosis and management of bipolar disorder in primary care: A DSM-5 update. Med Clin North Am 2014;98(5):1025-1048.” ABFM