when was the first time that since 164 months ago patient 95909 was prescribed a medication via pr?
select prescriptions.startdate from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 95909 ) and prescriptions.route = 'pr' and datetime(prescriptions.startdate) >= datetime(current_time,'-164 month') order by prescriptions.startdate asc limit 1