when was patient 27362 first prescribed the medication via the irr route in the last hospital visit?
select prescriptions.startdate from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 27362 and admissions.dischtime is not null order by admissions.admittime desc limit 1 ) and prescriptions.route = 'irr' order by prescriptions.startdate asc limit 1