when was patient 3118 last prescribed heparin flush midline (100 units/ml) until 14 months ago?
select prescriptions.startdate from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 3118 ) and prescriptions.drug = 'heparin flush midline (100 units/ml)' and datetime(prescriptions.startdate) <= datetime(current_time,'-14 month') order by prescriptions.startdate desc limit 1