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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 intravenous.mp OR iv.mp] AND [exp antiemetics OR anti-emetics.mp OR antiemesis.mp OR anti-emesis.mp OR anti-nausea.mp OR metoclopramide.mp OR cyclizine.mp OR ondansetron.mp] AND [exp vomiting OR vomiting.mp OR emesis.mp OR nausea.mp]) NOT postoperative.mp 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 1999 New Zealand	214 emergency department patients aged over 16 years with musculoskeletal trauma	Prospective Randomised Controlled Trial	Nauseau or vomiting at 2 hours	8 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 elderly	sampling was not consecutive, only severe nausea reported, only included patients with musculoskeletal trauma
Talbot-Stern J. & Paoloni R. 2000 USA	122 Emergency department patients over 16 years with pain	Prospective randomly controlled trial	nausea or vomiting at 30 and 60 minutes	no statistically significant difference between placebo and metoclopramide groups	no sample size calculation, no details of statistical analysis done, follow up only for 1 hour
			side effects between placebo and metoclopramide groups	3.7%(placebo) vs 7.9%(metoclopramide), not significant (dystonia/vertigo/dizziness/restlessness/drowsiness)
Paoloni R. & Talbot-Stern J. Nov 2002 Australia	250 Emergency Department patients over 16 years receiving opiates, 205 of which did not receive anti-emetics	Prospective observational study	Incidence of nausea at 30 and 60 minutes	4.9% 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 minutes	1.5% and 2.4% respectively, in those with no baseline vomiting
			Drowsiness baseline, 30 and 60 minutes	6.4%, 21,7% and 21% respectively
			Vital signs at baseline, 30 and 60 minutes	reduced P & BP (not clinically significant) and no change in respiratory rate

Comment(s)

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.

References

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