Although nonopiate analgesics may be particularly useful in the immediate postoperative period after major surgery, their use has been associated with haemodynamic adverse effects during postoperative pain treatment and in critically ill patients in intensive care. The effect of a single intravenous dose of metamizol (dipyrone) 2g, ketorolac 30mg and propacetamol 1g on haemodynamic variables and pain control in the immediate postoperative period after heart surgery is compared. Seventy-two patients undergoing elective coronary and/or heart valve surgery, were included in a cohort study of 1-years duration (1998). After weaning from mechanical ventilation and extubation, haemodynamic variables and a 4-point verbal rating pain scale were asseseed at base-line and 60 min after the administration of a single doses of metamizol, ketorolac or propacetamol. The Student's t-test for paired samples was used to compare changes produced by the study medications. A significant, but small, decrease in radial artery blood pressure was observed in all treatment groups which had little clinical relevance; no vasodilator effects were observed and ventricular function showed only minor changes: propacetamol decreased cardiac index by 10% and a 15% decrease in right ventricular work was also observed. Metamizol and ketorolac produced a 10% decrease in the left ventricular work index. Pain scores showed a statistically significant decrease in all treatment groups. The analgesic effects of metamizol, ketorolac and propacetamol were not associated with a clinically significant impairment in haemodynamic function when administered to haemodynamically stable patients.