Allopurinol dosage and effect on ischemia-reperfusion damage in elective and acute aortic surgery

To study the effect of a safe dosage of allopurinol on ischemia-reperfusion damage following aortic surgery, 24 patients undergoing either elective or acute aortic reconstruction, were randomized to receive allopurinol or placebo, yielding four groups: elective/placebo (EP), elective/allopurinol (EA), acute/placebo (AP) and acute/allopurinol (AA). Blood concentrations of allopurinol, oxypurinol, uric acid, malondialdehyde, ascorbic acid, and 99mTc-albumin were determined perioperatively. Adequate concentrations and biochemical activity of allopurinol and oxypurinol were obtained, without side-effects. Malondialdehyde did not increase perioperatively, but was significantly higher in acute surgery than in elective surgery intraoperatively. Yet, ascorbic acid levels and 99mTc-albumin disappearance were not different from groups EP and EA. No influence of allopurinol was found on malondialdehyde, ascorbic acid and 99mTc-albumin. An influence of allopurinol may have been obscured, as patients in group AA were more hypotensive than in group AP. In conclusion, adequate allopurinol concentration can be obtained with a safe dosage in abdominal aortic surgery. Signs of ischemia-reperfusion injury were found in acute surgery, not in elective surgery. Therefore, further investigation on the clinical effect of allopurinol is only useful in acute aortic surgery.