were prednisone, lr or milk of magnesia prescribed to patient 6990 in their last hospital visit?
select count(*)>0 from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 6990 and admissions.dischtime is not null order by admissions.admittime desc limit 1 ) and prescriptions.drug in ( 'prednisone', 'lr', 'milk of magnesia' )