a month before when was the last time that patient 27703 was prescribed medication via the tp route?
select prescriptions.startdate from prescriptions where prescriptions.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 27703 ) and prescriptions.route = 'tp' and datetime(prescriptions.startdate,'start of month') = datetime(current_time,'start of month','-1 month') order by prescriptions.startdate desc limit 1