what was the name of the first medication that was prescribed to patient 27451 until 63 months ago?
select prescriptions.drug from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 27451 ) and datetime(prescriptions.startdate) <= datetime(current_time,'-63 month') order by prescriptions.startdate asc limit 1