942
We performed a preliminary study in order to determine any difference between a non selective beta - blocker ( timolol ) and a selective beta - blocker ( betaxolol ) regarding CNS side effects .
 timolol, betaxolol
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Disease, Chemical 
Text: {0} 
Answer:
 timolol, betaxolol