instruction: how many hours has it been since patient 23436's last prescribed loperamide hcl during this hospital visit?
response: 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 = 23436 AND admissions.dischtime IS NULL) AND prescriptions.drug = 'loperamide hcl' ORDER BY prescriptions.startdate DESC LIMIT 1