Metoclopramide, used for almost 40 years in the prevention of post-operative nausea and vomiting, has no clinically relevant antiemetic effect in the doses currently used.
This is the conclusion of Dr I. Henzi (division of anaesthesiology, Geneva University hospitals, Switzerland) and colleagues. The doses currently used in clinical practice for this indication are too low, they say.
Writing in the British Journal of Anaesthesia (1999;83:761), they report a quantitative review of 66 randomised, controlled trials that involved 3,260 patients who received metoclopramide and 3,006 controls who received a placebo or no treatment.
The aim was to compare the antiemetic efficacy of prophylactic metoclopramide with placebo or no treatment for post-operative nausea and vomiting. The best documented doses of metoclopramide used in the studies were 10mg orally and IV for adults and 0.15mg/kg and 0.25mg/kg IV for children.
The authors found "no evidence of dose-responsiveness for efficacy or harm with metoclopramide in adults or children" and say that this is "strong evidence" that metoclopramide has no antiemetic effect at the doses used in the studies.
They comment that high doses of the drug are used commonly in chemotherapy but are 50 times higher than those used for post-operative nausea and vomiting. They end by calling for dose-finding studies to evaluate the efficacy of higher doses of metoclopramide for this indication.
Monmouth Pharmaceuticals, the manufacturer of metoclopramide (Maxolon) in the UK, declined to comment on the findings of the paper.