5897
Although ad hoc studies on their efficacy in the stroke prevention are currently lacking , newer antiplatelet agents ( mainly ticagrelor and prasugrel ) do not provide a significant better protection over and above aspirin and / or clopidogrel in the prevention of atherothrombotic stroke .
 Chemical: ticagrelor; Chemical: prasugrel; Chemical: aspirin; Chemical: clopidogrel
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: ticagrelor; Chemical: prasugrel; Chemical: aspirin; Chemical: clopidogrel