Motion sickness has plagued travelers, sailors, pilots, and commuters for centuries. Despite its widespread impact, treatment options have remained largely unchanged for decades, relying on antihistamines and anticholinergic drugs that often cause drowsiness and cognitive impairment. In December 2025, that long-standing gap in innovation finally closed.
The U.S. Food and Drug Administration approved Nereus (tradipitant) for the prevention of vomiting induced by motion in adults. This marks the first new pharmacologic treatment for motion sickness in more than forty years. Developed by Vanda Pharmaceuticals, Nereus introduces a modern neuropharmacology-based approach that targets the underlying biological pathway responsible for nausea and vomiting rather than masking symptoms.
This approval represents a major scientific and clinical milestone with implications for civilian travel, military readiness, and future treatments for nausea-related conditions.
Nereus is an oral neurokinin-1 (NK-1) receptor antagonist. It works by blocking the action of substance P, a neuropeptide involved in triggering nausea and vomiting in the central nervous system.
Unlike traditional motion sickness medications that affect histamine or acetylcholine receptors, tradipitant directly interrupts the signaling pathway that leads to vomiting. This mechanism has already been validated in other medical contexts, such as chemotherapy-induced nausea, but its application to motion sickness represents a new frontier.
Nereus is approved specifically for acute prevention of vomiting induced by motion in adults and is available by prescription only.
Motion sickness is often dismissed as a minor inconvenience, yet its prevalence and severity tell a different story. Research suggests that approximately 25 to 30 percent of adults experience motion sickness during common forms of travel such as cars, planes, or boats. In the United States alone, that translates to more than 65 million people.
Globally, up to one-third of the population is highly susceptible. While many experience mild symptoms, an estimated 5 to 15 percent suffer from severe or recurrent motion sickness that significantly interferes with daily life. These individuals often avoid travel entirely, alter career choices, or miss out on personal and professional opportunities.
Current treatment options include over-the-counter antihistamines like dimenhydrinate and meclizine or prescription anticholinergics such as scopolamine. These drugs are effective for some patients but are limited by side effects including sedation, dry mouth, blurred vision, and impaired alertness. For many, symptom control remains inadequate.
Motion sickness has long been recognized as more than a personal discomfort. During World War II, severe seasickness affected troop readiness during critical operations, including the D-Day invasion of Normandy. Soldiers crossing the English Channel experienced debilitating nausea and vomiting that compromised physical and cognitive performance.
As a result, motion sickness became a strategic concern, prompting early military research into antiemetic therapies. Despite these efforts, innovation stalled, leaving modern travelers and service members reliant on outdated pharmacologic tools.
The FDA approval of Nereus revives momentum in this long-neglected area of medicine.
The FDA’s decision was supported by data from three robust clinical studies, including two Phase 3 real-world trials conducted in challenging maritime conditions.
The Motion Syros study enrolled 365 participants with documented histories of motion sickness. Participants were exposed to provocative sea conditions aboard boats. Vomiting incidence in patients treated with Nereus ranged from 18.3 to 19.5 percent, compared to 44.3 percent in the placebo group. The results were statistically significant with a p-value of less than 0.0001.
The second Phase 3 study, Motion Serifos, included 316 participants. Vomiting rates among those receiving Nereus ranged from 10.4 to 18.3 percent, compared to 37.7 percent for placebo. This represented a risk reduction of more than 50 to 70 percent, with strong statistical significance.
Across all studies, Nereus demonstrated consistent efficacy and a safety profile appropriate for acute use.
Motion sickness occurs due to a sensory mismatch between visual, vestibular, and proprioceptive inputs. When the brain receives conflicting information about movement, it activates pathways associated with nausea and vomiting.
Substance P plays a central role in this response by binding to NK-1 receptors in the brainstem. This activation triggers the vomiting reflex. Nereus works by selectively blocking NK-1 receptors, preventing substance P from initiating this cascade.
By targeting the core biological mechanism, Nereus represents a more precise approach compared to older drugs that broadly suppress the nervous system.
In placebo-controlled trials, the most commonly reported adverse reactions were somnolence and fatigue. These effects occurred in approximately 6 to 12 percent of participants, depending on dose.
Because Nereus may impair mental or physical abilities, patients are advised to avoid driving or operating heavy machinery, particularly when combined with other central nervous system depressants.
Tradipitant is metabolized by the CYP3A4 enzyme, meaning strong CYP3A4 inhibitors can increase drug exposure and risk of side effects. Use in patients with severe renal impairment or any degree of hepatic impairment is not recommended.
The safety and effectiveness of Nereus have not been established in pediatric patients. Data regarding use in pregnancy and lactation are limited.
The FDA approval of Nereus opens the door to broader applications of NK-1 receptor antagonism. Vanda Pharmaceuticals is continuing clinical development of tradipitant for additional indications, including:
These programs highlight the broader relevance of substance P mediated pathways across multiple gastrointestinal and neurologic conditions.
Vanda Pharmaceuticals has indicated plans to launch Nereus in the United States in the coming months. As a prescription-only medication, access will depend on healthcare provider evaluation and insurance coverage.
For patients who have struggled with ineffective or intolerable motion sickness treatments, Nereus represents a meaningful new option grounded in modern neuroscience.
The approval of Nereus is significant not only because it introduces a new drug but because it redefines how motion sickness can be treated. It validates decades of research into neurokinin signaling and demonstrates that long-standing conditions can still benefit from innovation.
For millions of adults affected by motion-induced vomiting, this approval offers renewed hope for safer, more effective prevention and improved quality of life.
This article is for informational and educational purposes only. It does not constitute medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional regarding medical conditions, medications, or treatment decisions. Information is based on publicly available FDA announcements, clinical trial data, and manufacturer disclosures as of December 2025.
