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Are routine anti-emetics required with iv morphine?

Three Part Question

in [patients receiving IV morphine] is the [routine use of anti-emetics] effective in [preventing vomiting]

Clinical Scenario

A 34 year old man presents to the accident and emergency department with a fractured right ankle. You prescribe intravenous morphine and the nurse asks you to also prescribe an anti-emetic, as this is standard practice. You wonder if the anti-emetic is really necessary.

Search Strategy

Medline 1966-09/2004 using the Ovid interface and The Cochrane Library, Issue 3, 2004.
Medline: ([exp morphine OR exp narcotics OR opiate$.mp OR exp analgesics, opioid OR analges$.mp] AND [exp injections, intravenous or OR] AND [exp antiemetics OR OR OR OR OR OR OR] AND [exp vomiting OR OR OR]) NOT LIMIT to human AND English language.
The Cochrane Library: ((morphine or narcotics or opiates or opioid or analgesia) AND (intravenous or iv) AND (antiemetics or anti-emetics or antiemesis or anti-emesis or anti-nausea or metoclopramide or cyclizine or ondansetron) AND (vomiting or nausea)) NOT (postoperative or post-operative)

Search Outcome

Altogether 100 papers were found in Medline of which 98 were not relevant to the study question. Twenty-five papers were found in Cochrane, 2 of which were relevant (one of these papers was also indexed in Medline). These 3 papers are shown in the table below.

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Lambie B. et al
New Zealand
214 emergency department patients aged over 16 years with musculoskeletal traumaProspective Randomised Controlled TrialNauseau or vomiting at 2 hours8 patients vomited, 2 (1.9%) in placebo and 6 (5.4%) in metoclopramide group. 2 in placebo group had severe nausea, 0 in metoclopramide group. Significantly more vomiting in elderlysampling was not consecutive, only severe nausea reported, only included patients with musculoskeletal trauma
Talbot-Stern J. & Paoloni R.
122 Emergency department patients over 16 years with painProspective randomly controlled trialnausea or vomiting at 30 and 60 minutesno statistically significant difference between placebo and metoclopramide groupsno sample size calculation, no details of statistical analysis done, follow up only for 1 hour
side effects between placebo and metoclopramide groups3.7%(placebo) vs 7.9%(metoclopramide), not significant (dystonia/vertigo/dizziness/restlessness/drowsiness)
Paoloni R. & Talbot-Stern J.
Nov 2002
250 Emergency Department patients over 16 years receiving opiates, 205 of which did not receive anti-emeticsProspective observational studyIncidence of nausea at 30 and 60 minutes4.9% and 9.3% in those with no nausea at baseline (mild in 92% & 76% respectively)no control group, no ethics approval, follow up only for 1 hour
Incidence of vomiting at baseline, 30 and 60 minutes1.5% and 2.4% respectively, in those with no baseline vomiting
Drowsiness baseline, 30 and 60 minutes6.4%, 21,7% and 21% respectively
Vital signs at baseline, 30 and 60 minutesreduced P & BP (not clinically significant) and no change in respiratory rate


It appears that there is a low incidence of nausea and vomiting after administration of intravenous morphine and this is not improved by anti-emetic use. In addition there appeared to more vomiting in the metoclopramide group than placebo (though not statistically significant). There are also more reported side effects with the use of anti-emetics than with placebo (not significant)

Clinical Bottom Line

Use of anti-emetics routinely with intravenous morphine in the emergency department should not be done.

Level of Evidence

Level 2 - Studies considered were neither 1 or 3.


  1. Lambie B. Chambers J. Herbison P. The Role of prophylactic anti-emetic therapy in emergency department patients receiving intravenous morphine for musculoskeletal trauma Emergency Medicine 1999 (11) 240-243
  2. Talbot-Stern J. Paoloni R. Prophylactic metoclopramide is unnecessary with intravenous analgesia in the ED American Journal of Emergency Medicine 2000; 18:653-657
  3. Paoloni R. Talbot-Stern J. Low incidence of nausea and vomiting with intravenous opiate analgesia in the ED American Journal of Emergency Medicine November 2002;20:604-8