Hospitalists often default to ondansetron when treating nausea in hospitalized patients, even though the drug may not always be the best choice. That was one of the key messages from a session at SHM Converge, where Dr. Annie Massart, an associate professor at Emory University School of Medicine, outlined a practical, evidence-based approach to managing nausea. Her talk covered the physiology of nausea, the pharmacology of antiemetics, and how to make better bedside decisions.
Dr. Massart started by acknowledging a reality many internists recognize: most receive little formal training in nausea management. As a result, ondansetron has become the default empiric choice. She explained that its widespread use may have less to do with superiority and more to do with timing and exposure. Ondansetron entered the market in the 1990s as the first anti-serotonergic antiemetic, was aggressively marketed, and quickly became familiar to clinicians in the absence of broader education on alternatives. One of her primary goals for the session was to expand hospitalists’ understanding of the full range of available options.
Ondansetron still has a place. But the talk emphasized that relying on a single agent without considering the underlying cause can lead to persistent symptoms and unnecessary side effects. The core idea: identify which pathway is driving the nausea, then pick a medication that targets it.
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Dr. Massart reviewed the neuroanatomic pathways involved in nausea and the receptors associated with each. The vestibular system signals nausea through muscarinic acetylcholine and histamine 1 receptors. The gastrointestinal tract primarily involves 5-hydroxytryptamine 3 (5-HT3) receptors, 5-HT4 receptors, and dopamine receptors. The brain’s vomiting center and the chemoreceptor trigger zone rely on overlapping sets of receptors, including those for dopamine, neurokinin-1, and 5-HT3. The cerebral cortex also contributes, with gamma-aminobutyric acid and histamine 1 receptors playing a role.
Using this framework, she pushed an etiology-centered approach. Rather than reflexively ordering a single medication, clinicians should identify which pathway is most likely driving a patient’s symptoms and select antiemetics accordingly. She stressed the importance of scheduled dosing rather than as-needed use, noting that consistent receptor blockade is often more effective. If nausea persists, she recommended adding a second agent with a different mechanism of action instead of discontinuing and cycling through individual medications.
This kind of shift — from a one-size-fits-all habit to a targeted strategy — requires more than just knowing the pathways. It demands a willingness to question long-standing prescribing patterns, especially when the go-to drug has a strong marketing history behind it. The evidence suggests that many alternatives work just as well, or better, for specific causes of nausea.
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A significant portion of the talk addressed QTc prolongation and the risk of torsade de pointes (TdP). Dr. Massart reviewed available data on common antiemetics, focusing particularly on ondansetron. She acknowledged that a single, 4-mg, IV dose can increase the QTc interval by approximately 16 to 20 milliseconds but pointed out that more recent evidence suggests the overall risk of TdP may be overestimated. She also clarified that the 2017 American Heart Association guidelines recommend obtaining a baseline QTc in patients with known QT prolongation or other risk factors when starting TdP-associated medications, including older age, female sex, or electrolyte abnormalities.
Dr. Massart then turned to haloperidol. She explained that it partially fell out of favor after an expanded U.S. Food and Drug Administration QTc warning in 2007. She noted that this shift was influenced in part by the drug’s age and reputation, rather than evidence of excessive risk. In fact, haloperidol’s QTc prolongation risk is comparable to that of serotonin antagonists such as ondansetron, and she recommended keeping the total daily dose under 5 mg when monitoring is a concern.
She also reviewed data on metoclopramide. As of 2024, the FDA’s adverse event reporting system included only five cases of TdP and sixteen cases of prolonged QTc associated with the drug. While acknowledging these risks, she stressed that neurological adverse effects, including tardive dyskinesia, are ultimately the greater concern as they are much more common.
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Discussion then shifted to phenothiazines, including prochlorperazine and promethazine. Dr. Massart noted that the literature on QTc risk for this class is limited. She cited the 2025 National Full Cancer Network guidelines, which acknowledge the potential for QTc prolongation but do not provide specific quantitative estimates. She also emphasized an important safety point: IV promethazine should never be used, given its acidic formulation and the risk of severe tissue injury if extravasation or improper injection occurs.
Dr. Massart highlighted olanzapine as an underutilized option for nausea management. She reviewed evidence supporting its effectiveness in chemotherapy-induced vomiting, as well as its role in improving appetite and promoting weight gain in patients with advanced cancer. She noted additional benefits in broader cancer-related nausea and postoperative settings, emphasizing that once-daily dosing and reduced need for multiple antiemetics make olanzapine particularly appealing for patients with a high pill burden.
To close, she discussed QTc-friendly antiemetic strategies, focusing on oral agents such as olanzapine and aprepitant, which have less impact on cardiac ion channels compared with many IV medications. She also highlighted palonosetron, a second-generation serotonin antagonist with more selective receptor interactions, and reviewed data from a meta-analysis showing that isopropyl alcohol wipes can be surprisingly effective for nausea — often outperforming placebo and even medications like ondansetron. Brief inhalation of isopropyl alcohol wipes is rapidly and highly effective, and can be carried and deployed extremely easily by hospitalists on the wards.
