Lipid emulsion as rescue therapy in lamotrigine overdose

Lamotrigine is a sodium channel blocking agent that is widely prescribed for treatment of seizure. Although life-threatening effects are rarely observed in overdose, some previous reports have described the occurrence of cardiac toxicity. The management of sodium channel blocking agent-induced cardiotoxicity conventionally requires sodium bicarbonate administration. Recent case reports describe intravenous lipid administration as a successful treatment for refractory cardiovascular collapse induced by sodium channel blocking medications.

The objective of this study is to report the use of intravenous lipid emulsion as adjunctive therapy in a case of lamotrigine overdose in which electrocardiographic changes were unresponsive to bicarbonate therapy.

We report a case of intentional lamotrigine overdose in a 50-year-old woman who lost consciousness and developed electrocardiographic aberrations, including widening of QRS with occurrence of left bundle branch block. The patient was initially treated with sodium bicarbonate without effect. Recovery of cardiac conduction was rapidly achieved after infusion of a 20% lipid emulsion. The exact mechanism of action of lipid emulsion is not fully understood. The lipophilic properties of lamotrigine suggest that it was partially removed by the plasmatic lipid emulsion.

This case provides additional insight into the potential benefit of using lipid emulsion in refractory sodium channel blocking intoxications.