how many days have pass since the last time patient 97733 was prescribed thiamine hcl on their current hospital visit?
select 1 * ( strftime('%j',current_time) - strftime('%j',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 = 'thiamine hcl' order by prescriptions.startdate desc limit 1