The pharmacy and nursing time requirements, quality of postoperative pain control, and cost of patient-controlled analgesia (PCA) and intramuscular (i.m.) analgesic therapy were studied. All timings were conducted with a stopwatch on a single nursing unit that primarily receives gynecologic surgery patients. The various work elements involved in each type of therapy were timed individually. Both quality of analgesia and cost were evaluated in a prospective, randomized study in hysterectomy patients. I.M. patients received meperidine hydrochloride 75-100 mg every three to four hours as needed. PCA patients had access to morphine sulfate 1 mg or meperidine hydrochloride 10 mg, with a six-minute lockout period. The patients scored their pain every four hours. Direct costs for PCA were calculated as drug cost plus tubing cost plus form cost plus maintenance cost plus depreciation cost. Direct costs for i.m. therapy consisted of the cost of drugs. The total mean nursing time per patient was 16.9 minutes for PCA and 10.7 minutes for i.m. therapy. Pharmacy time per patient was 5.1 minutes longer for PCA than for i.m. therapy. Thirty-six hysterectomy patients (17 i.m. and 19 PCA) were enrolled in the study of pain control and cost. Among i.m. patients, 64% of the pain scores were mild or worse, compared with 40% for PCA patients. The median pain scores were moderate for i.m. patients and mild for PCA patients. Scores tended to be lower for PCA patients at 16 and 20 hours. Although equal numbers of patients in the two groups experienced nausea, i.m. patients needed more doses of antiemetics than PCA patients.(ABSTRACT TRUNCATED AT 250 WORDS)