when did patient 78221 receive his/her last prescription for glycopyrrolate when they visited the hospital first time?
select prescriptions.startdate from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 78221 and admissions.dischtime is not null order by admissions.admittime asc limit 1 ) and prescriptions.drug = 'glycopyrrolate' order by prescriptions.startdate desc limit 1