Antiepileptic Drug Treatment in Community-Dwelling Older Patients with Epilepsy: A Retrospective Observational Study of Old- Versus New-Generation Antiepileptic Drugs

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.

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.

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.

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.

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.