COMPARISON OF METOCLOPRAMIDE AND ONDANSETRON FOR THE PREVENTION OF NAUSEA AND VOMITING AFTER INTRATHECAL MORPHINE

Nausea and vomiting remain unpleasant side effects of intrathecal (i.t .) morphine and of the numerous therapies tried, only prophylactic int ravenous (i.v.) metoclopramide has been reported to be promising. Seve nty-three patients, scheduled for orthopaedic prosthesis surgery of th e hip or knee were studied. They received 4 mL of plain bupivacaine an d 0.3 mg of preservative-free morphine i.t. for anaesthesia. The test drugs given in a double-blind and randomized fashion, were either meto clopramide 20 mg, three times, at 6 h intervals (23 patients), ondanse tron, 8 mg, twice, at 12 h intervals (25 patients), or 0.9% saline thr ee times, at 6 h intervals (25 patients). The occurrence of nausea, vo miting and pain was followed for 24 h. The incidences of nausea and vo miting were 60% (15/25) and 56% (14/25) in the saline group, 52% (12/2 3) and 48% (11/23) in the metoclopramide group, and 52% (13/25) and 40 % (10/25) in the ondansetron group. Incidences of severe vomiting were 24, 35 and 12%, respectively. Eight patients in the saline group, sev en in the metoclopramide and 10 in the ondansetron group did not need additional opioids for post-operative pain relief. We conclude that, m etoclopramide and ondansetron were not better than saline in the preve ntion of post-operative emesis induced by intrathecal morphine.