how much oxycodone-acetaminophen has been prescribed to patient 57050 in this hospital encounter?
select sum(prescriptions.dose_val_rx) from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 57050 and admissions.dischtime is null ) and prescriptions.drug = 'oxycodone-acetaminophen'