how many hours has it been since patient 10624 has been prescribed lidocaine-prilocaine first on the current hospital encounter?
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 = 10624 and admissions.dischtime is null ) and prescriptions.drug = 'lidocaine-prilocaine' order by prescriptions.startdate asc limit 1