Lamotrigine May Cause Rare Immune System Reaction, FDA Warns

The Food and Drug Administration (FDA) in April issued a safety announcement warning that the anticonvulsant medication lamotrigine (sold under the brand name Lamictal) can cause a rare but serious immune reaction. Lamotrigine is approved for the treatment of patients with epilepsy and maintenance treatment of bipolar I disorder to delay the time to occurrence of mood episodes in adults 18 and older.

According to the agency, there have been several reports of hemophagocytic lymphohistiocytosis (HLH) in patients taking lamotrigine. HLH, which triggers an uncontrolled immune system response, typically presents as a persistent fever (usually greater than 101°F). HLH can lead to severe problems with blood cells and organs throughout the body such as the liver, kidneys, and lungs.

“Health care professionals should be aware that prompt recognition and early treatment are important for improving HLH outcomes and decreasing mortality,” the FDA notice stated. “Evaluate patients who develop fever or rash promptly, and discontinue lamotrigine if HLH or another serious immune-related adverse reaction is suspected and an alternative etiology for the signs and symptoms cannot be established.”

The FDA noted that since lamotrigine’s approval in 1994, the agency has identified eight cases worldwide of confirmed or suspected HLH associated with the medicine in children and adults. “This number includes only reports submitted to FDA and found in the medical literature, so there are likely additional cases about which we are unaware,” the notice stated.

In the eight cases examined, symptoms of HLH were reported to have occurred within 8 to 24 days following treatment initiation. “We determined there was reasonable evidence that lamotrigine was the cause of HLH in these eight cases based on the timing of events and the order in which they occurred. The patients in these cases required hospitalization and received drug and other medical treatments, with one dying.”

The agency is now requiring that the prescribing information in the lamotrigine label contain a warning about the risk of HLH. Other serious adverse reactions already included in the drug label include serious rashes, suicidal thoughts and actions, and aseptic meningitis.

Health care providers are encouraged to report adverse events involving lamotrigine to the FDA MedWatch program. ■