Abstracts

RATIONALE: Asterixis is a known adverse event in antiepileptic drug intoxication and in different metabolic encephalopathies, which, as of yet has not been reported in patients being treated with oxcarbazepine,lamotrigine or vigabatrin. We have observed asterixis in patients being treated with these 3 drugs despite serum concentrations within the therapeutic range. METHODS: 4 patients with epilepsy showed new onset movement induced negative myoclonias after add-on of a new antiepileptic drug. The first, a 29 year old woman with a post-traumatic partial epilepsy and terminal kidney insufficiency presented with unclear drop attacks after receiving add-on oxcarbazepine to phenobarbitone and valproic acid. The second, a 58 year old woman with generalized epilepsy, mental retardation and a severe obstructive sleep-apnoe-syndrome became in addition to valproic acid and phenytoin add-on lamotrigine. After this change in medication the nursing staff reported that the patient kept dropping objects out of her hand. The third, a 42 year old woman with a non-classifiable epilepsy and a previous anterior callosotomy was given lamotrigine as an add-on to valproic acid and pheneturide after which she developed a massive flapping tremor. The forth, a 60 year old woman reported jerks during walking after add-on vigabatrin to carbamazepine. We performed ictal polygraphic video-EEG-recordings (16 channel EEG, 8 channel surface EMG) in all 4 patients. RESULTS: All 4 patients showed during voluntary movements silent periods in the EMG with a duration of 50-300 milliseconds. These atonic or negative myoclonic episodes were recorded in all innervated muscles. The symptomatology disappeared in all patients after discontinuation of the newly introduced add-on drug. CONCLUSIONS: Our results show that also new antiepileptic drugs can cause asterixis as a side effect with serum-concentrations within the therapeutic range.