when patient 97733 was prescribed for the last time polyethylene glycol in this hospital visit?
select prescriptions.startdate from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 97733 and admissions.dischtime is null ) and prescriptions.drug = 'polyethylene glycol' order by prescriptions.startdate desc limit 1