what drug has been prescribed to patient 23237 for the last time in 12/this year?
select prescriptions.drug from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 23237 ) and datetime(prescriptions.startdate,'start of year') = datetime(current_time,'start of year','-0 year') and strftime('%m',prescriptions.startdate) = '12' order by prescriptions.startdate desc limit 1