The Senior Care Study. The optimal use of medications in acutely ill older patients. Geriatric assessment units have improved pharmacotherapy for their patients by decreasing the number of medications prescribed. The Senior Care Study, a randomized controlled trial, compared a multidisciplinary-team approach to patient care to the standard medical practice of the institution. As a part of the trial, the effectiveness of an interdisciplinary team intervention in improving the use of medications was studied. Study goals were to decrease medications used, decrease unnecessary medications, and improve medication choices in our acutely ill inpatient population. A pharmacist interviewed all experimental patients and patient records, and presented medication concerns and recommendations at a team conference. Medications were counted on admission and on the third day, sixth week, and third month after randomization. Medications were paired with patient problems. Medication:problem pairs were judged as inappropriate choices if there were potential side effects that would affect patient function, and if better alternatives were available. The 215 control and 221 experimental patients in the study were similar in age, sex, place of origin, and number of medications on admission. Experimental patients took fewer medications than controls on the third day (5.3 versus 5.9, P less than .05). Experimental patients received fewer multiple unpaired medications (11% versus 19%, P less than .025) and fewer inappropriate medication choices (20% versus 37%, P less than .005). The results suggest that the team intervention was effective in improving pharmacotherapy in the acute-care setting. 