Abstracts

Rationale: Tics, chorea, downward deviation of eyes, oculomotor apraxia, blepharospasm, involuntary excessive eye blinking, but not oculogyric crisis (OGC) have been reported as manifestations of Lamotrigine (LTG) overdosage . Here we report a case series of four patients (3 males and a female) with LTG induced OGC. Methods: Patients who developed OGC on increased doses of LTG (due to inadvertent ingestion and/or dose escalation), who did not have preexisting movement disorders, and who had no recurrence of the episode after the reduction of dose of LTG were included. Retrospective review of the charts was done. Results: Average age was 12.25 years (range 3 -25). Two patients had partial seizures, one had generalized tonic-clonic seizures and one had absence seizures. In all the cases, OGC was the main manifestation that brought the patient to medical attention. The number of OGC episodes ranged from 1 to 20 per day for 2 days to 3.5 months. The duration that each episode lasted ranged from 2 seconds to 4 hours. Mean blood level of LTG before the period of toxicity was 7mcg/ml (6-12), during was 15.5mcg/ml (9-20) with a mean dose of 13mg/kg/day (7-25), and after dose reduction was 8mcg/ml (7-9). Mean duration of LTG therapy before the occurrence of 1st episode was 4.5 months. Other antiepileptic drugs used concomitantly include clonazepam (2 patients), ethosuximide (1), valproate (1), topiramate (1) and levetiracetam (2). Associated symptoms were dizziness, lightheadedness, nausea, sleepiness and tremulousness. Conclusions: OGC is one of the manifestations of LTG toxicity