what was the first prescribed time for amino acids 4.25% w/ dextrose 5% since 02/2105 for patient 23969?
select prescriptions.startdate from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 23969 ) and prescriptions.drug = 'amino acids 4.25% w/ dextrose 5%' and strftime('%y-%m',prescriptions.startdate) >= '2105-02' order by prescriptions.startdate asc limit 1