ACTA ANAESTHESIOLOGICA SCANDINAVICA, vol.46, no.8, pp.1025-1030, 2002 (SCI-Expanded)
Background: We tested whether, after major abdominal surgery, the addition of magnesium or ketamine to tramadol for intravenous (IV) patient-controlled analgesia (PCA) improved analgesia and lowered pain scores, compared to a PCA containing only tramadol.