Quantifying unused orders for as-needed medications.

Nonuse of as-needed (p.r.n.) medication orders in a university hospital was quantified. A total of 882 patient charts for the last six months of 1984 were reviewed (seven randomly selected patients per month from each of 21 medical-surgical services). Orders for p.r.n. medications were quantified by therapeutic category and by whether the order was written on admission. Use or nonuse of orders was determined from pharmacy records of doses administered. Of 7735 p.r.n. orders, 4793 (62%) were unused. By therapeutic category, antacids were the least prescribed p.r.n. medications but also had the highest rate of nonuse. In every therapeutic category, the rate of unused orders was higher for orders written on the day of admission than for subsequent orders. By patient's medical-surgical service, the percentages of p.r.n. orders unused ranged from 50% for renal transplant patients to 81% for ophthalmology patients. Nonuse of p.r.n. medications in all therapeutic categories decreased as length of stay increased; the overall rate of nonuse was 80% for patients hospitalized for two days or less. Reduction of the number of p.r.n. orders written but not used should begin in two areas: orders written on day of admission, and orders for patients with short hospital stays.