Supply problems of antiseizure medication are common among epilepsy patients in Germany

To evaluate the frequency of reported antiseizure medication (ASM) supply problems among patients with epilepsy (PWE) in Germany.

The Epi2020 study was a multicenter study focusing on different healthcare aspects of adult PWE in Germany. In addition to basic clinical and demographic characteristics, PWE were asked to answer a questionnaire regarding supply difficulties regarding their ASM, and if they had to discontinue ASM treatment due to supply problems. Generic switch of medication was recorded, and adverse effects were measured using the Liverpool Adverse Events Profile (LAEP) scale. Data were analyzed to detect predictors of supply problems.

In total, 434 PWE with a mean age of 40 years (median 37 years, SD = 15.5, range: 18-83 years, 254 female) participated in this study. 53.7% of PWE (n = 233) reported that at least once in the past 12 months their ASM was not available at the pharmacy, and 24.9% (n = 108) reported having experienced ASM supply problems three times or more during the past 12 months. Patients with epilepsy treated with carbamazepine and zonisamide reported frequent problems with availability in 45.8% and 44.8% respectively, whereas those treated with lacosamide and valproate reported supply problems less frequently (17.0% and 16.4%, respectively). Nine patients (2.1%) were unable to take their ASM as prescribed at least once in the past 12 months due to supply problems. Forty-nine patients (11.3%) reported having to switch ASM due to supply difficulties with generic replacement occurring in 39.4% (n = 171) of patients. Those with supply problems were more likely to be treated with more ASMs and scored higher on the LAEP.

Supply problems with ASM are frequent among PWE in Germany and are reported for older and newer ASMs. Supply problems contribute to ASM nonadherence and are positively correlated with the number of ASM taken and adverse events.