instruction: what are the four most commonly prescribed medications for patients, which were also previously prescribed to patients with 1000 ml flex cont: lactated ringers iv soln during the same month until 2104?
response: SELECT t3.drugname FROM (SELECT t2.drugname, DENSE_RANK() OVER (ORDER BY COUNT(*) DESC) AS c1 FROM (SELECT patient.uniquepid, medication.drugstarttime FROM medication JOIN patient ON medication.patientunitstayid = patient.patientunitstayid WHERE medication.drugname = '1000 ml flex cont: lactated ringers iv soln' AND STRFTIME('%y', medication.drugstarttime) <= '2104') AS t1 JOIN (SELECT patient.uniquepid, medication.drugname, medication.drugstarttime FROM medication JOIN patient ON medication.patientunitstayid = patient.patientunitstayid WHERE STRFTIME('%y', medication.drugstarttime) <= '2104') AS t2 ON t1.uniquepid = t2.uniquepid WHERE t1.drugstarttime < t2.drugstarttime AND DATETIME(t1.drugstarttime, 'start of month') = DATETIME(t2.drugstarttime, 'start of month') GROUP BY t2.drugname) AS t3 WHERE t3.c1 <= 4