Introduction: The use of antiepileptic drugs (AEDs) in older patients with epilepsy is challenged by polypharmacy and decreased drug elimination. Newer AEDs have a lower potential for drug interactions and are reported to be better tolerated by the elderly than old-generation AEDs.
Objective: The objective of this study was to evaluate AED use and the related adverse event rate in an outpatient cohort of older patients with epilepsy.
Methods: We retrospectively reviewed the computerized database and medical records of all the patients aged ≥60 years who visited our epilepsy outpatient clinic (Assaf Harofeh Medical Center, Zerifin, Israel) during a 4-year period from February 2012 to February 2016. In this study, phenytoin, valproic acid, carbamazepine, phenobarbital, clobazam, and clonazepam were defined as old-generation AEDs. Gabapentin, levetiracetam, lamotrigine, topiramate, oxcarbazepine, lacosamide, and perampanel were defined as new-generation AEDs.
Results: The study group included 115 patients aged 60-90 years (mean 70.5 ± 7.8 years), 70 (61%) of whom were men. Co-morbidities were present in 98.3% of the patients, including neuropsychiatric illnesses in 21.2%. Present medical treatment included new-generation AEDs in 49 (44.5%) and both old- and new-generation AEDs in 20 (18.2%) patients. The most commonly used current AEDs were phenytoin, gabapentin, levetiracetam, and lamotrigine. Adverse reactions mainly included fatigue and CNS-related symptoms, and were more frequent among patients treated with new-generation AEDs than in those treated with old-generation AEDs or a combination of old- and new-generation AEDs; however, these reactions were mostly related to levetiracetam treatment. The likelihood of levetiracetam-related adverse events was increased by slow levetiracetam titration [defined as a weekly dose increase of ≤250 mg/day in this study; odds ratio (OR) 16.35, 95% confidence interval (CI) 2.94-90.98], and by low- (OR 5.68, 95% CI 1.40-22.95) and high (OR 4.24, 95% CI 1.28-14.02) levetiracetam dosages compared with patients treated with lamotrigine or gabapentin.
Conclusions: New-generation AEDs were administered to most of the patients in this outpatient clinic-based cohort of older patients with epilepsy. In order to decrease levetiracetam-related adverse events in this age group, we suggest that a slower titration rate (e.g., an increase of ≤125 mg/day each week) and lower maximal dosage (e.g., 1500 mg/day) of the drug should be considered.