over 3 days post-operatively. The costs of PCA and i.m. therapies per patient were used to calculate the The present study contrasted the pharmaco-ecocost-benefit (cost of treatment vs. nursing time) and nomics and analgesic efficacy of intramuscular (i.m.)cost-effectiveness (cost of treatment vs. SPID) anaopioid treatment with a parenteral disposable patientlyses. Both treatments initially provided comparable controlled analgesia (PCA) system in two groups of analgesia, but PCA was more efficient after 16 h and 20 female patients (ASA I-II, aged 35-69 years) schedsignificantly reduced nursing time for uled for abdominal hysterectomy. The PCA group repain treatment (PCA=61±4 min, i.m.=88±5 min; ceived a continuous infusion of 1.5 mg h −1 piritramide, P<0.001). Functional recovery was not different for a -opioid receptor agonist, with incremental doses either treatment. Cost analysis indicated a better costof 1.5 mg (lock-out interval=15 min). The i.m. group benefit ratio for the i.m. treatment (0.35 vs. 1.1 for received 0.3 mg kg −1 piritramide i.m. when requested PCA treatment), but a similar cost-effectiveness for by the patient with a minimum interval of 5 h. Pain both treatments (PCA=1.9 Belgian Francs (BEF) unit −1 intensity, sedation and the functional recovery of the SPID; i.m.=1.7 BEF unit −1 SPID). patients were followed for 72 h post-operatively. The sum of pain intensity differences (SPID) was used as a measure of analgesic efficiency. Equipment and drug costs, and the demand on nursing time were recorded post-operative analgesia.