Tradipitant (Nereus) for the Prevention of Motion Sickness

Tradipitant (Nereus) is a P/neurokinin-1 receptor antagonist labeled for the prevention of motion-induced vomiting in adults.¹ P/neurokinin-1 is one of five receptors associated with nausea and vomiting and can be found in the vomiting center of the medulla oblongata and the chemoreceptor trigger zone.²

Tradipitant has no significant contraindications. Because tradipitant is a cytochrome 3A4 substrate, strong CYP3A4 inhibitors may increase the risk of somnolence and other adverse effects. Patients should avoid driving or other activities that require mental alertness after taking tradipitant.

Tradipitant has not been studied in pregnant patients, but animal studies have shown no significant adverse effects. Breastfeeding infants should be monitored for somnolence because tradipitant is likely excreted in breast milk.

Tradipitant is generally well-tolerated. Adverse effects include dose-dependent fatigue (6% to 8%), somnolence (6% to 12%), and headache (7% to 10%).^3–5

Tradipitant has been studied in three randomized, double-blind, placebo-controlled trials, with a reduction in motion-induced vomiting in each study.^2–4 In two of these studies, a total of 681 participants with a history of motion sickness were randomized to receive a single dose of tradipitant 85 mg, tradipitant 170 mg, or placebo 60 minutes before a 2-to 5-hour boat trip. Individuals with chronic nausea were excluded from the trials. Both doses of tradipitant significantly reduced rates of vomiting compared with placebo (10.4% to 19.5% vs 37.7% to 44.3%; number needed to treat = 3 to 5). The secondary end point of worst nausea assessed during the boat trip was not significantly improved in either study.^2,3 In the third study, a total of 126 participants with a history of motion sickness were randomized to receive a single dose of tradipitant 170 mg or placebo 60 minutes before a 1- to 5-hour vehicle trip. Tradipitant reduced rates of vomiting compared with placebo (17.5% vs 39.7%; P < .0001; number needed to treat = 5).⁴

Tradipitant has not been directly compared with current standard of care for motion-induced vomiting. It also has not been studied for other causes of vomiting or in patients with body mass index greater than 40 kg/m², pregnant patients, or children.

Tradipitant is available for $85 per capsule at https://nereus.us/. In comparison, over-the-counter dimenhydrinate and meclizine cost less than $10 for 12 tablets. Scopolamine costs about $20 for one patch.⁶

Tradipitant is administered as a single 85-mg or 170-mg dose 60 minutes before an event expected to cause motion-induced vomiting. It should be taken on an empty stomach. No more than 170 mg of tradipitant should be taken within 24 hours.

Tradipitant is well-tolerated and effective for reducing motion-induced vomiting. It is more expensive than other available medications but is an alternative option that uses a different mechanism of action for patients who have not responded to other treatments.