when was the first time in the last hospital visit patient 64292 is prescribed levetiracetam?
select prescriptions.startdate from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 64292 and admissions.dischtime is not null order by admissions.admittime desc limit 1 ) and prescriptions.drug = 'levetiracetam' order by prescriptions.startdate asc limit 1