how much cosyntropin, for the first time in 02/this year, was prescribed to patient 74159?
select prescriptions.dose_val_rx from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 74159 ) and prescriptions.drug = 'cosyntropin' and datetime(prescriptions.startdate,'start of year') = datetime(current_time,'start of year','-0 year') and strftime('%m',prescriptions.startdate) = '02' order by prescriptions.startdate asc limit 1