Lamotrigine distribution in two postmortem cases.

Lamotrigine (Lamictal) is a new anticonvulsant drug recently approved for use in the United States. Although a therapeutic range for lamotrigine has not been definitively established, a range of between 2 and 14 mg/L has been reported. Two cases are presented in which lamotrigine was identified in cases investigated by the Office of the Chief Medical Examiner, State of Maryland. Lamotrigine was identified by gas chromatography-nitrogen-phosphorus detection following an alkaline extraction. A DB-5 column provided analytical separation; no derivatization was required. Confirmation was achieved by full scan electron ionization gas chromatography-mass spectrometry. In Case 1, primidone (11 mg/L) and phenobarbital (5.5 mg/L) were found in the heart blood in addition to lamotrigine (8.3 mg/L); in Case 2, no drugs other than lamotrigine (52 mg/L) were detected in the heart blood. The peripheral blood concentration in Case 2 was 54 mg/L. The liver lamotrigine concentrations in the two cases were 41 and 220 mg/kg. The medical examiner ruled that the cause of death in Case 1 was seizure disorder and the manner of death was natural. In Case 2, the medical examiner ruled that the cause of death was lamotrigine intoxication and the manner of death was undetermined.