Ondansetron (Zofran) Is Not Effective for Travel Sickness
Ondansetron (Zofran) is not effective for treating travel sickness and should not be used for this purpose. Multiple studies have demonstrated that ondansetron fails to prevent motion sickness symptoms in susceptible individuals 1, 2, 3.
Evidence Against Ondansetron for Travel Sickness
A study specifically examining high-dose ondansetron for motion sickness found no difference between ondansetron, dimenhydrinate, and placebo in highly susceptible subjects 1:
- No differences in number of head movements tolerated
- No differences in rotation time
- No differences in symptom questionnaire scores
Another study evaluating ondansetron for seasickness prevention showed:
- No statistically significant reduction in seasickness symptoms compared to placebo
- No difference in performance test results 2
Research on the mechanism of action reveals that while ondansetron can inhibit gastric tachyarrhythmia (abnormal stomach rhythms associated with motion sickness), this effect is not sufficient to prevent the development of nausea and other motion sickness symptoms 3
Why Ondansetron Fails for Motion Sickness
The mechanism of nausea in motion sickness appears to differ from that of toxin-induced nausea (like chemotherapy-induced or postoperative nausea) 2. This explains why ondansetron works well for:
- Postoperative nausea and vomiting 4
- Chemotherapy-induced nausea 3
- General undifferentiated nausea in emergency settings 5
But fails specifically for motion/travel sickness.
Alternative Approaches for Travel Sickness
While the provided evidence doesn't specifically address alternative treatments for travel sickness, it's worth noting that:
- Traditional antihistamines (like dimenhydrinate) also showed poor efficacy in the comparative study 1
- The CDC guidelines focus on traveler's diarrhea prevention and treatment rather than motion sickness 6
Clinical Implications
- Do not prescribe ondansetron for patients seeking medication for travel sickness
- The evidence consistently shows that ondansetron does not provide benefit over placebo for this specific indication
- This remains true despite ondansetron's established efficacy for other forms of nausea and vomiting
- The lack of efficacy was demonstrated across different motion sickness scenarios (rotation-induced 1, 3 and seasickness 2)
Common Pitfalls to Avoid
- Don't assume that because ondansetron works well for other types of nausea, it will work for travel sickness
- Don't confuse traveler's diarrhea (an infectious condition) with travel/motion sickness (a vestibular/sensory mismatch condition)
- The mechanisms underlying different types of nausea vary significantly, explaining why medications effective for one type may be ineffective for another