5894
Although aspirin and thienopyridines have proved their efficacy in the prevention of arterial thrombotic events , limited efficacy , increased risk of bleeding , significant inter - individual variability in the response and extended duration of action that cannot be reversed if the need for haemostasis or emergency surgery arises represent major limitations of these drugs .
 Chemical: aspirin; Chemical: thienopyridines
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: aspirin; Chemical: thienopyridines