Meptazinol and morphine compared: a study using systolic time intervals.

Changes in systolic time intervals following the administration of either morphine (0.1 mg/kg) or meptazinol (1 mg/kg) were studied in 12 patients admitted to hospital for intra-abdominal operations. The changes in these indices of cardiac performance were small. However, in 5 of the 6 patients who received morphine, the changes were in a direction suggesting negative inotropism, whereas the changes following meptazinol (6 patients) consistently suggested an improved ventricular performance.