Ep 127 EM Drugs that Work and Drugs that Don’t Part 2 – Antiemetics, Angioedema, Oxygen

In this Episode 127 Drugs that Work and Drugs that Don't Part 2 - Antiemetics, Angioedema and Oxygen, with Justin Morgenstern and Joel Lexchin we discuss the evidence for various antiemetics like metoclopramide, prochlorperazine, promethazine, droperidol, ondansetron, inhaled isopropyl alcohol and haloperidol as well as why should not use an antiemetic routinely with morphine in the ED. We then discuss the evidence for various drugs options for a potpourri of true emergencies like angioedema and hyperkalemia, and wrap it up with a discussion on oxygen therapy... Podcast production, sound design & editing by Anton Helman Written Summary and blog post by  Anton Helman July, 2019 Cite this podcast as: Helman, A. Morgenstern, J. Lexchin J. EM Drugs that Work and Drugs That Don't Part 2. Emergency Medicine Cases. July, 2019. https://emergencymedicinecases.com/em-drugs-that-work-part-2. Accessed [date] Go to part 1 of this 2-part podcast on EM drugs that work and drugs that don't Antiemetics: Are they all equally effective? A Cochrane review compared mean nausea scores at 30 minutes of metoclopramide, prochlorperazine, promethazine, droperidol, ondansetron and placebo in ED patients with nausea [1]. The only statistically significant change in baseline VAS at 30 minutes was for droperidol (which is not available in Canada), in a single trial. No other drug was statistically significantly superior to placebo. There is no definite evidence to support the superiority of any one drug over any other drug. Patients in the placebo arms often reported clinically significant improvement in nausea at 30 minutes which may reflect the cyclical nature of nausea. If an antiemetic is used, choice of drug should be dictated by patient preference, side effects and cost. Sedation is common to all of these antiemetics except ondansetron. Don't forget that all the antipsychotic antiemetics (prochlorperazine, promethazine, droperidol, haloperidol) can worsen Parkinsonian symptoms through their dopaminergic effects and so should be avoided in patients with Parkinson's disease. Is inhaled isopropyl alcohol the first line antiemetic of choice? A Cochrane review suggests a moderate level of evidence for a significant reduction in time to 50% reduction in nausea scores (about 3 points on a 10 point scale) when comparing inhaled isopropyl alcohol (holding an alcohol swab 1-2cm below the nares and inhaling for 5 minutes) to standard antiemetics in postoperative patients with nausea, with fewer patients who received isopropyl alcohol requiring rescue antiemetics [2]. In one ED RCT, when compared to placebo normal saline solution a similar 50% reduction/3 point difference was seen at 10 minutes [3]. In another ED RCT, when comparing ondansetron 4mg po to inhaled isopropyl alcohol the mean decrease in nausea scores were about 1/10 for ondansetron and 3/10 for isopropyl alcohol, with no difference in the proportion of patients requiring rescue mediations (about 1/4) [4]. None of the trials with isopropyl alcohol inhalation found any side effects. IV haloperidol as antiemetic for gastroparesis and cyclical vomiting syndrome Haloperidol 5mg IV has been shown to decrease both pain scores and nausea when compared to placebo in gastroparesis [5]. Remarkably, patients in the  haloperidol arm had a 27% admission rate compared to 72% in the placebo arm. Haloperidol has also been shown in case reports of patients with cannabis hyperemesis syndrome to be effective in doses ranging from 2.5mg-5mg [6]. Take home: In general, none of the traditional antiemetics (metoclopramide, prochlorperazine, promethazine, droperidol, ondansetron) are better than placebo at improvin...