[Switching from clopidogrel hydrogen sulfate to clopidogrel besylate. Impaired antiplatelet effect in patients with ischemic stroke].

The use of antiplatelet medications, such as acetylsalicylic acid (ASA), a combination of dipyridamol with ASA and also clopidogrel, is of great importance for the secondary prevention of ischemic stroke or transient ischemic attacks. In addition to the known form of clopidogrel hydrogen sulfate (CHS) a further clopidogrel salt, clopidogrel besylate (CB), has also been available since May 2008. The presented case illustrates that in patients with a history of cerebrovascular disease the antiplatelet response of CB can be diminished in comparison to CHS. Therefore we recommend testing the antiplatelet effectiveness when changing patient medication from CHS to CB.