Delivery problems and switch of the manufacturer of antiseizure medications - An update of an online survey of patient's experiences in Germany and other German-speaking countries.

In the last decade there is an increasing frequency of sudden generic switches of antiseizure medications (ASMs) due to delivery problems. We here explored the patient's views toward generic substitution of ASMs and their experiences with delivery problems and switches of the manufacturer. A questionnaire already used in 2011 was updateded and published on the website of a patient's organisation from March 2022 until November 2022. 54.4 % of the responders reported delivery problems. Delivery problems were reported from Germany by a higher number of responders than from Switzerland. To 83.7 % of the responders the delivery problems were communicated by the pharmacists. In 41.9 % of these the delivery problems were coped by generic substitution. In 33 % of the latter breakthrough seizures occurred. 26 % of the respondents with experience of a change of the manufacturer not due to a delivery problem reported breakthrough seizures after being substituted. The majority of patients denied having been well informed about the possible consequences of a switch of the manufacturer. A thorough counselling on the low risks caused by change of the manufacturer and the need for good adherence to further reduce the risks should be part of the general information about their treatment with ASMs for people with epilepsy.