ABSTRACT
In patients with epilepsy, nonadherence to agreed antiepileptic drug (AED) treatment may result in seizure relapse, and at worst sudden unexpected death. The aim of this study was to examine the extent of both unintentional and intentional nonadherence among Norwegian patients with refractory epilepsy and try to identify possible risk factors. At the National Centre for Epilepsy in Norway, 333 consecutive adult in- and outpatients with refractory epilepsy participated in an anonymous survey about adherence to drug treatment. Twenty-two percentages admitted that they sometimes or often forgot to take their drugs as scheduled, and 19% reported that they, rarely, sometimes or often intentionally did not follow the AED treatment plan agreed upon with their physician. Young age and depression were significantly correlated with unintentional nonadherence. Intentional nonadherence was associated with young age (36 years or younger). We found nonadherence not to be associated with any specific AED. In conclusion, about one-fifth of patients with refractory epilepsy admitted that they did not adhere to the agreed drug treatment plan, either intentionally or unintentionally. Measures to reduce nonadherence in this patient group may improve seizure control and should be tailored to address both unintentional and intentional lack of adherence.
ABSTRACT
PURPOSE: Antiepileptic drugs (AEDs) are increasingly used, and knowledge about adverse effects is scarce based on clinical studies. The purpose of the present study was to characterise adverse effects reports of AEDs in Norway relative to changes in utilisation in various indications from population-based data to elucidate important safety aspects of use of AEDs. METHODS: Aggregated data of adverse effects reported for AEDs in Norway from the EudraVigilance-database (2004-2013) in addition to indication-specific use of AEDs during 2004-2015 from the Norwegian Prescription Database were used. RESULTS: The use of AEDs increased twofold the last decade due to use in psychiatry and neuropathic pain: lamotrigine, pregabalin, gabapentin, valproate, and carbamazepine. There were 1593 adverse effects reported (403 Individual Case Safety Reports, 2/3 women), 0-95 years (mean 46). Most adverse effects were reported for pregabalin (593), carbamazepine (265), lamotrigine (206), gabapentin (144), and valproate (119), where pregabalin had by far the highest reports in relation to the number of users. The most frequently reported adverse drug effects included rash, dizziness, cross-sensitivity reactions, and pyrexia. Overall, nervous system disorders constitute the largest organ class with the majority of the reports. Reporting of fatal outcomes is mandatory, and sudden unexplained death in epilepsy (SUDEP) was reported in 34 occasions. CONCLUSIONS: This study demonstrates that most adverse effects reported concerned AEDs increasingly used in non-epilepsy indications: neuropathic pain (pregabalin, gabapentin, carbamazepine) and psychiatry (lamotrigine, valproate, carbamazepine). Pregabalin had the highest prevalence of adverse effects reported in relation to number of users. This elucidates an important part of pharmacovigilance for improved safety and considerations in clinical practice.
