19179
Patients aged > 70 years who received at least two prescriptions for donepezil , rivastigmine , galantamine and memantine between January 2006 and December 2010 were included in the study .
 Chemical: donepezil; Chemical: rivastigmine; Chemical: galantamine; Chemical: memantine
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: donepezil, rivastigmine, galantamine, memantine 
Answer:
 Chemical: donepezil; Chemical: rivastigmine; Chemical: galantamine; Chemical: memantine