how many dose of tricor has been prescribed to patient 29741 in the first 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 = 29741 and admissions.dischtime is not null order by admissions.admittime asc limit 1 ) and prescriptions.drug = 'tricor'