Management of nausea in ambulance: tips and tricks evidence-based

Practical Strategies for the First Responder: How to Address the Most Common (and Least Glamorous) Emergency Challenge" When we climb into the ambulance, we often expect adrenaline, sirens, and life-saving interventions. In the daily reality of emergency response, however, managing nausea represents a clinical challenge that is both common and underestimated. It may not be glamorous, but inadequate management can result in patients in difficulty, airway compromise, and logistical complications for the crew. This article proposes a practical, evidence-based approach that is, I hope, pragmatic enough to address this problem between one road bump and another.

Essential Background

• Prevalence: 10-30% of patients in EMS context manifest nausea or vomiting.

• Pathophysiology in summary: interaction between chemoreceptor trigger zone, 5-HT₃ and D₂ receptors, and vagal stimulation - this is why targeted pharmacological choice makes the difference.

• Clinical implications: risk of aspiration, dehydration, interference with monitoring, and operational inefficiency of the crew

BOX – Red Flags Emesis + headache → suspect CT Coffee-ground vomit → GI bleed Chest pain → it's not just nausea

Tips and Tricks for Antiemetics: The Winning Triad

When it comes to managing nausea and vomiting in the ambulance, having a clear strategy can make a real difference between a calm intervention and an unpleasantly chaotic one. Let's start with the basics: the first intervention, simple and immediate, consists of using isopropyl alcohol (IPA). Often underestimated, this method involves bringing a gauze soaked in IPA close to the patient's nose, leveraging a rapid olfactory stimulation with surprisingly quick effectiveness (within 3-5 minutes). Recent meta-analyses from 2023 demonstrate that its efficacy can compete with 5-HT₃ receptor antagonist drugs, albeit with a limited duration of action. If IPA is not sufficient, our therapeutic arsenal is enriched with more powerful drugs. Ondansetron clearly emerges as the first-line pharmacological option thanks to its ability to halve episodes of nausea and vomiting compared to metoclopramide, as demonstrated by recent meta-analyses from 2025. Available in various formulations (IV, IM, and ODT – orodispersible tablets), it is a well-tolerated and effective drug, though requiring particular attention to QTc monitoring, which must not exceed 480 ms to avoid cardiac complications. Metoclopramide, on the other hand, remains a valid alternative, especially in contexts where ondansetron is not available or well-tolerated. It is inexpensive, widely used, and works well as a D₂ antagonist prokinetic, but be careful with the recommended maximum dosage (30 mg/day) to avoid acute dyskinetic reactions. Finally, for the most refractory and difficult cases, droperidol can represent an effective rescue therapy, provided it is used with caution due to known adverse effects such as QTc prolongation and hypotension risk. Let's reserve it, therefore, for cases that truly test our clinical abilities.

Intervento	Meccanismo d'azione	Considerazioni cliniche
Inhaled IPA	Olfactory stimulation with rapid antiemetic effect (3-5 min). 2023 Meta-analysis: efficacy comparable to 5-HT₃ antagonists	Limited duration of action. Note: the odor may be unpleasant for personnel not accustomed to it
Ondansetron 4 mg IV/IM/ODT	Selective 5-HT₃ antagonist, reduces vomiting risk by 50% vs metoclopramide (2025 meta-analysis, n=861	QTc monitoring essential (contraindicated if >500 ms)
Metoclopramide 10 mg IV	Metoclopramide 10 mg IV Prokinetic agent with D₂ antagonist action, economical and widely available option	Risk of acute dyskinetic reactions. EMA limitation: max 30 mg/24h
Droperidol 2.5 mg IV (optional)	High-potency D₂ antagonist, effective as rescue therapy	Caution with QTc prolongation and hypotension—reserve for refractory cases

How to Manage Nausea | Operational Protocol

1. Assessment & red flags – vital parameters, EKG if long QT suspected.

2. IPA aromatherapy immediately: gauze soaked near the nose.

3. Ondansetron 4 mg IV/IM if moderate-severe nausea or IPA insufficient.

4. Metoclopramide 10 mg IV if ondansetron unavailable/not tolerated.

5. VAS-nausea monitoring every 5-10 min; watch for extrapyramidal effects or QTc alterations.

6. Documentation drug-dose-route, pre/post VAS, attached EKG.

   
   

Five Practical Tips to Address Nausea in the Ambulance

• IPA = starter pack: quick, zero IV access, costs less than adhesive tape.

• Ondansetron superstar: effective, but remember the QT (especially if the "beep-beep" warning screams).

• Metoclopramide: yes, but use the hourglass—max 30 mg/day.

• Personalize: pregnancy (benefits > risks? use clinical scales), pediatrics 0.1 mg/kg ondansetron.

• It's not just medication: lateral position, suction ready, fresh air. The patient thanks you (and so does your crew).

Focus on Sumie et al. Study (2025): New Evidence on Ondansetron Superiority

The recent meta-analysis by Sumie and colleagues, published this year in the Journal of Anesthesia, offers important insights relevant to the pre-hospital context. Although focused on the pediatric post-tonsillectomy setting (5 RCTs, n=861), the conclusions support preferential use of ondansetron in the ambulance.

Key transferable results for the EMS context:

• Relative risk reduction: Ondansetron reduces nausea/vomiting risk by 52% compared to metoclopramide (RR 0.48, 95% CI 0.31-0.75)

• Opioid-independent efficacy: Regression analysis demonstrated ondansetron's efficacy remains constant regardless of administered opioid dose

• Reduced hospitalization: Reduced admission times (mean difference -26.92 minutes) in the ondansetron group

• Safety profile: Although only two studies monitored extrapyramidal reactions, no events were reported in either group

These data, combined with EMS studies showing increasing ondansetron adoption in pre-hospital protocols, confirm the advantage of using this drug in our setting. The 50% reduction in emetic episode risk represents a significant advantage not only for patient comfort but also for preventing complications like aspiration, particularly risky during transport.

Conclusion

Effective nausea management in the pre-hospital environment represents a fundamental aspect of daily clinical practice that, while not attracting media attention, has a significant impact on care quality and patient safety. A systematic approach integrating IPA aromatherapy, targeted pharmacotherapy with ondansetron (or metoclopramide as an alternative) and appropriate positional measures can transform a potentially traumatic experience into a manageable transport.

After all, we prefer the patient to tell their ambulance experience, not have their stomach's contents tell the story for them!

References

• Kimber JS, et al. (2023). Efficacy of isopropyl alcohol aromatherapy compared to 5-HT₃ antagonists for nausea management. Eur J Clin Pharmacol, 79:1525-35.

• Sumie M, et al. (2025). Effect of ondansetron and metoclopramide on postoperative nausea and vomiting in children undergoing tonsillectomy with or without adenoidectomy: a systematic review with meta-analysis. J Anesth, epub ahead of print.

• European Medicines Agency. (2013). Metoclopramide: updated recommendations on use.

• Caffey MR, Maria S, Brewster L, Ireland MF. Antiemetic management preferences for paramedic providers: a cross-sectional survey. Australasian Journal of Paramedicine. 2016;13(2). doi:10.33151/ajp.13.2.217.