Dialysis for Lamotrigine Intoxication in a Teenager

Introduction: Lamotrigine (LTG) is a rare cause of acute intoxication. A 1993 pharmocokinetic study of a dose of LTG was conducted in healthy volunteers, patients w CKD and ESRD on iHD. The elimination half-life of LTG was approximately 25 h in subjects w normal renal function and 50 h in uremic patients. iHD shortened the elimination half-life from 59.6 +/- 28.1 h during the interdialysis period to 12.2 +/- 6.4 h during the dialysis period; 17% of the dose was extracted by HD. Clinical reports of 2 to 5 iHD treatments have been associated w neurologic improvement. LTG levels > 25 μg/mL have been associated w severe toxicity in adults. Ingestions > 4.5gm of LTG have been associated w severe morbidity and mortality. Case Description: 16 yo F w h/o depression intentionally ingested a total of 6 g of LTG and unknown small amounts of lurasidone and fluoxetine. She was taken to ER for headache and dizziness 3 h post ingestion. At 27 h after ingestion, she developed hypotension requiring pressor support and had a GTC seizure requiring intubation for airway protection. There was no AKI. Poison Control recommended hemodialysis to clear LTG. CVVHDF was initiated 41 h after ingestion and continued until 55 h after ingestion. She was switched to 4 h iHD when she was stable off pressors. CVVHDF was resumed at 89 h after ingestion for 12 h, then discontinued w Poison Control advice. She had improvements to her mental status and was extubated at 120 h. LTG levels were sent daily but results were not available until dialysis was discontinued (Figure). She was transferred to inpatient psychiatry on day 8. Discussion: Sixty-three percent of LTG was cleared after a combination of CVVHDF and iHD within 48 hours. Subsequent CVVHDF for 12 hours cleared an additional 19% of LTG. A rebound in LTG level was seen the next day off dialysis; however, patient already had recovery from AMS. Due to the severity of clinical presentation and delay in LTG levels resulting, we performed dialysis for 3 consecutive days in this patient w clinical improvement.Lamotrigine intoxication