403
No significant treatment effects were found , although there were trends towards a reduction in feeling tense and nervous by both drugs compared with placebo during the 7 . 5 % CO ( 2 ) challenge , and a reduction in alertness generally in the venlafaxine group compared with the pregabalin group .
 Chemical: CO ( 2 ); Chemical: venlafaxine; Chemical: pregabalin
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: CO ( 2 ), venlafaxine, pregabalin 
Answer:
 Chemical: CO ( 2 ); Chemical: venlafaxine; Chemical: pregabalin