Studies of drugs given before anaesthesia. XXIV: Metocloramide with morphine and pethidine.

When given with pethidine 100 mg or morphine 10 mg as preanaesthetic medication, 10 and 20 mg of metoclopramide cause a reduction in postoperative nausea and vomiting in women undergoing a standard operation with a standard anaesthetic technique. The preoperative emetic effects of pethidine are almost completely abolished by metoclopramide. An additional 10-20 mg of metoclopramide, given i.m. at the end of the operation markedly reduces the emetic effects of pethidine premedication but has less effect when morphine has been given. The evidence suggests that the ineffectiveness of metoclopramide, relative to other antiemetics, is because of its brevity of action.