how many hours have elapsed since patient 12775 first recieved a prescription for diltiazem extended-release on this hospital visit?
select 24 * ( 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 = 12775 and admissions.dischtime is null ) and prescriptions.drug = 'diltiazem extended-release' order by prescriptions.startdate asc limit 1