Risk and Severity of Akathisia Following Administration of Metoclopramide in the Emergency Department

Prophylactic antiemetics for adults receiving intravenous opioids in the acute care setting

BACKGROUND

Physicians often prescribe opioids for pain in the acute care setting. Nausea and vomiting are well-described adverse events, occurring in over one-third of patients. Prophylactic antiemetics may be one option to reduce opioid-associated nausea and vomiting. However, these medications also have their own adverse effects, so it is important to understand their efficacy and safety prior to routine use. This is a review of randomized controlled trials comparing prophylactic antiemetics versus placebo or standard care for preventing opioid-associated nausea and vomiting.

OBJECTIVES

To assess the effects of prophylactic antiemetics for nausea and vomiting in adults (aged 16 years or older) receiving intravenous opioids in the acute care setting.

SEARCH METHODS

We searched CENTRAL (the Cochrane Library), MEDLINE (OVID), Embase (OVID) from inception to January 2022, and Google Scholar (17 January 2022). We also searched the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) and screened reference lists.

SELECTION CRITERIA

We included randomized controlled trials of prophylactic antiemetics versus placebo or standard care in adults prior to receiving an intravenous opioid.

DATA COLLECTION AND ANALYSIS

Two review authors (MG, JNC) independently determined the eligibility of each study according to the inclusion criteria. Two review authors (MG, GDP) then independently extracted data, assessed risk of bias, and determined the certainty of evidence using GRADE. Our primary outcomes were the occurrence of nausea, vomiting, and adverse events. Secondary outcomes included nausea severity, number of vomiting episodes, and number of participants requiring antiemetic rescue therapy. We presented outcomes as risk ratios (RR) for dichotomous data (e.g. presence of vomiting, presence of nausea, number of participants requiring rescue medication, adverse events) and mean difference (MD) or standardized mean difference for continuous data (e.g. number of vomiting episodes, nausea severity) with 95% confidence intervals (CI).

MAIN RESULTS

We included three studies involving 527 participants (187 women and 340 men) with a mean age of 42 years.  All studies used intravenous metoclopramide (10 mg) as the intervention and a placebo for the comparator. No studies assessed any other antiemetic or compared the intervention to standard care. Compared to placebo, metoclopramide did not reduce vomiting (RR 1.18, 95% CI 0.26 to 5.32; low-certainty evidence) or nausea (RR 0.55; 95% CI 0.15 to 2.03; low-certainty evidence) and there was no difference in adverse events (RR 2.34, 95% CI 0.47 to 11.61; low-certainty evidence).  No data were available regarding the number of vomiting episodes. Metoclopramide did reduce the severity of nausea compared with placebo (MD -0.49, 95% CI -0.75 to -0.23; low-certainty evidence) but did not reduce the need for rescue medication (RR 1.86, 95% CI 0.17 to 20.16; low-certainty evidence).  Two studies were at unclear risk of bias for random sequence generation, one for blinding of outcome assessors, one for incomplete outcome data, and two for selective reporting. The studies were at low risk of bias for all remaining components.

AUTHORS' CONCLUSIONS

There was no evidence that prophylactic metoclopramide affected the risk of vomiting, nausea, or the need for rescue medication when provided prior to intravenous opioids in the acute care setting. There was a clinically insignificant difference in nausea severity when comparing prophylactic metoclopramide with placebo. Overall, the evidence was of low certainty. Future research could better delineate the effects of prophylactic antiemetics on specific populations, and new studies are needed to evaluate the use of other prophylactic antiemetic agents, for which there were no data.

A prospective, randomized, double-blind trial of intravenous chlorpromazine versus intravenous prochlorperazine for the treatment of acute migraine in adults presenting to the emergency department

OBJECTIVE

To compare the efficacy of intravenous chlorpromazine versus intravenous prochlorperazine for the treatment of acute migraine in adults presenting to the emergency department (ED).

BACKGROUND

Migraine is a common, incapacitating neurological condition. Although chlorpromazine and prochlorperazine are known to be safe, efficacious treatments for migraine, they have never been directly compared.

DESIGN

We performed a prospective, randomized, double-blind clinical trial at a tertiary hospital in Melbourne, Australia. Adults aged 18-65 years, who presented with migraine, were eligible for recruitment. Sixty-six patients were randomized to either chlorpromazine 12.5 mg or prochlorperazine 12.5 mg, both infused in 500 ml of sodium chloride 0.9% over 30 min. Headache severity score, nausea severity score, and the presence of photophobia and phonophobia were assessed at 0, 30, 60, and 120 min. Adverse effects and the need for rescue therapy were recorded. The primary outcome was a reduction in headache severity score from baseline at 60 min post-commencement of the study medicine infusion.

RESULTS

Sixty-five patients were included in the analysis. There was a median reduction in headache severity score at 60 min of 3.0 (interquartile range 1.0-4.0) in the chlorpromazine arm versus 2.0 (1.0-4.0) in the prochlorperazine arm (median difference -0.5 (95% confidence interval, -1.9 to 0.9)). We saw no evidence of a difference in secondary outcomes at 30, 60, or 120 min. Side effects were reported in 16/32 (50%) patients in the chlorpromazine group versus 7/33 (21%) in the prochlorperazine group (p = 0.020). Rescue therapy was required in 7/32 (22%) patients in the chlorpromazine group versus 12/33 (36%) in the prochlorperazine group (p = 0.277).

CONCLUSIONS

Both chlorpromazine and prochlorperazine are efficacious treatments for acute migraine in adult patients presenting to the ED. This trial found no evidence of superiority of either agent over the other. Caution should be used when prescribing these medicines in the borderline hypotensive patient; in that circumstance, prochlorperazine should be preferentially used.

Review article: Prophylactic metoclopramide for patients receiving intravenous morphine in the emergency setting: a systematic review and meta-analysis of randomized controlled trials

The objective of the present study was to conduct a systematic review and meta-analysis of randomized controlled trials, comparing metoclopramide with placebo, for preventing vomiting in patients who have received i.v. morphine for acute pain in the emergency setting, and to determine the level of evidence supporting the use of prophylactic metoclopramide in this population. Comprehensive systematic electronic searches were conducted of MEDLINE, EMBASE and the Cochrane Library for randomized controlled trials addressing the clinical question. Reference lists of identified articles were hand-searched. Methodologically appropriate clinical trials identified in the search process were included in a meta-analysis to provide a pooled estimate of effect. Three randomized controlled trials fulfilled the search criteria. All three studies were included in the final meta-analysis that demonstrated an overall result of no difference between metoclopramide and placebo for the primary outcome of vomiting (odds ratios 0.72; 95% confidence intervals 0.11-4.58). There was little evidence that routine prophylactic administration of metoclopramide following the administration of i.v. morphine for acute pain management in the emergency setting is clinically beneficial. Routine metoclopramide administration might expose patients to a risk of harm which is not justifiable given a lack of evidence of benefit.

Education initiative improves the evidence-based use of metoclopramide following morphine administration in the emergency department

OBJECTIVE

We aimed to evaluate a multifaceted education initiative designed to reduce the prophylactic use of metoclopramide.

METHODS

This was a pre- and post-intervention trial undertaken in a single ED. All ED doctors and nurses were targeted. The intervention comprised a specifically designed, 19-slide 'e-learning module', accessible via the ED intranet, supplemented by in-service training and a range of reminder techniques (posters, emails and drug room flyers). The primary end-point was the proportion of patients administered metoclopramide prophylactically with their initial morphine dose. Data were collected on random samples of patients who received morphine, using explicit medical chart review.

RESULTS

Both pre- and post-intervention periods were of 3 month duration. The charts of 146 cases were reviewed in each period. In the post-intervention period: * The proportion of patients administered metoclopramide prophylactically decreased from 22.6% to 4.1% (difference 18.5% [95% CI 10.3-26.7], P < 0.001) * The proportion of patients administered metoclopramide appropriately (for known morphine sensitivity, established nausea and rescue anti-emesis) rose marginally from 28.8% to 32.9% (difference 4.1% [95% CI -7.2-15.4], P = 0.53) * There was a 12.7% decrease in the number of ampoules of metoclopramide issued to the ED without a concurrent rise in the issue of other anti-emetic drugs

CONCLUSION

The education initiative resulted in a significant improvement in the evidence-based use of metoclopramide.