Drugs for preventing postoperative nausea and vomiting

  • Review
  • Intervention




Drugs can prevent postoperative nausea and vomiting, but their relative efficacies and side effects have not been compared within one systematic review.


The objective of this review was to assess the prevention of postoperative nausea and vomiting by drugs and the development of any side effects.

Search methods

We searched The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 2, 2004), MEDLINE (January 1966 to May 2004), EMBASE (January 1985 to May 2004), CINAHL (1982 to May 2004), AMED (1985 to May 2004), SIGLE (to May 2004), ISI WOS (to May 2004), LILAC (to May 2004) and INGENTA bibliographies.

Selection criteria

We included randomized controlled trials that compared a drug with placebo or another drug, or compared doses or timing of administration, that reported postoperative nausea or vomiting as an outcome.

Data collection and analysis

Two authors independently assessed trial quality and extracted outcome data.

Main results

We included 737 studies involving 103,237 people. Compared to placebo, eight drugs prevented postoperative nausea and vomiting: droperidol, metoclopramide, ondansetron, tropisetron, dolasetron, dexamethasone, cyclizine and granisetron. Publication bias makes evidence for differences among these drugs unreliable. The relative risks (RR) versus placebo varied between 0.60 and 0.80, depending upon the drug and outcome. Evidence for side effects was sparse: droperidol was sedative (RR 1.32) and headache was more common after ondansetron (RR 1.16).

Authors' conclusions

Either nausea or vomiting is reported to affect, at most, 80 out of 100 people after surgery. If all 100 of these people are given one of the listed drugs, about 28 would benefit and 72 would not. Nausea and vomiting are usually less common and, therefore, drugs are less useful. For 100 people, of whom 30 would vomit or feel sick after surgery if given placebo, 10 people would benefit from a drug and 90 would not. Between one to five patients out of every 100 people may experience a mild side effect, such as sedation or headache, when given an antiemetic drug. Collaborative research should focus on determining whether antiemetic drugs cause more severe, probably rare, side effects. Further comparison of the antiemetic effect of one drug versus another is not a research priority.

Plain language summary

Drugs for preventing nausea and vomiting after surgery

We found eight drugs that reliably prevented nausea or vomiting after surgery. The drugs prevented nausea or vomiting in three or four people out of every 10 who would have vomited or felt nauseated with a placebo. We did not find reliable evidence that one drug was better than another. A person's age or sex, the type of surgery, or the time the drug was given did not change the effect of a drug. When drugs were given together, their effects simply added. Side effects were mild and affected four out of 100 people for the two drugs most studied.

Either nausea or vomiting are reported to affect, at most, 80 out of 100 people after surgery. If all 100 of these people are given a drug, about 28 would benefit and 72 would not. Nausea or vomiting are usually less common and therefore drugs are usually less useful.

Doctors should research how often drugs cause severe side effects.