Use of antiepileptic drugs among community-dwelling persons with Alzheimer's disease in Finland

Persons with Alzheimer's disease (AD) may be particularly susceptible to the adverse drug reactions associated with anti-epileptic drugs (AEDs). The objective of this study was to investigate the national pattern of AED use among community-dwelling persons with and without AD in Finland. All persons (n = 28,093) with a diagnosis of AD in 2005 were identified by the Social Insurance Institution of Finland (SII). The SII also identified comparison persons without AD individually matched in terms of age (±one year), gender, and region. Records of all reimbursed drug purchases in 2005 were extracted from the Finnish National Prescription Register. Conditional logistic regression was used to calculate unadjusted and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for reimbursed AED use. Persons with and without AD were aged 42 to 101 (mean 80.0) years, with men comprising 32.2% (n = 9,048) of persons. Epilepsy was diagnosed for 2.1% of persons with AD compared to 1.3% of persons without AD (OR 1.66; 95% CI, 1.45 to 1.89). AEDs were used by 5.0% (n = 1417) of persons with AD compared to 3.4% (n = 955) persons without AD (adjusted OR 1.33; 95% CI, 1.21 to 1.46). The annual prevalence of phenytoin, clonazepam, valproic acid, and oxcarbazepine use was higher among persons with AD. In contrast, pregabalin use was lower among persons with AD (adjusted OR 0.83; 95% CI, 0.70 to 0.99). Use of older AEDs is more prevalent among persons with AD, despite persons with AD being particularly vulnerable to adverse drug reactions associated with many older AEDs.