ISSN: 2161-0495
Therese Becker, Angela L Chiew and Betty SH Chan
Lamotrigine poisoning is usually benign causing only mild to moderate neurological and cardiovascular effects. However, there have been case reports of lamotrigine poisoning leading to intractable seizures, sudden cardiovascular collapse and death. It has not been clear if haemodialysis can effectively remove lamotrigine. We provide pharmacokinetic data on a large lamotrigine overdose that was managed with intermittent haemodialysis.
We present a case of a 23-year-old (90 kg) female who presented to hospital 2 hours post ingestion of 17.8 g of lamotrigine and 9 g of quetiapine. Her initial Electrocardiogram (ECG) showed a sinus tachycardia with normal intervals. Over time this progressed to a right bundle branch pattern progressive QRS widening and T wave changes. She was commenced on Continuous Veno-Venous Heamodiafiltration Therapy (CVVHDF) but the circuit clotted. Eleven hours post ingestion she still had ongoing ECG changes despite a bolus of 100 mmol of 8.4% sodium bicarbonate. She was commenced on Intermittent Haemodialysis (IHD) 16 hours post ingestion. Lamotrigine levels were collected and the extraction ratio of lamotrigine during IHD was 0.4 with a mean clearance of 78 ml/min. The half-life of lamotrigine was significantly shorter during IHD, 4.1 hours versus 30.4 hours post IHD. She was extubated 42 h post ingestion and made a full recovery. She acknowledged at that time she only took 9 g of lamotrigine.
This case demonstrates that intermittent haemodialysis is effective in removing lamotrigine in acute overdose.