how many hours have elapsed since patient 11826 was prescribed tacrolimus in their current hospital visit for the first time?
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 = 11826 and admissions.dischtime is null ) and prescriptions.drug = 'tacrolimus' order by prescriptions.startdate asc limit 1