What diagnosis should I use for prescribing Zofran (ondansetron) for a patient with motion sickness from a cruise?

Appropriate Diagnosis Code for Prescribing Ondansetron for Seasickness

For prescribing ondansetron (Zofran) for seasickness from a cruise, the most appropriate diagnosis code would be "Motion Sickness" (ICD-10 code T75.3) as ondansetron is not FDA-approved for this indication and is not recommended as first-line therapy for motion sickness.

Understanding Motion Sickness and Treatment Options

• Motion sickness is a common syndrome occurring upon exposure to certain types of motion, thought to be caused by conflict between the vestibular, visual, and other proprioceptive systems 1
• Nausea is the hallmark symptom, often preceded by stomach awareness, malaise, drowsiness, and irritability 1
• Air travel and sea travel can significantly affect individuals, causing symptoms ranging from mild discomfort to severe nausea and vomiting 2

Evidence Regarding Ondansetron for Motion Sickness

• Ondansetron has not been shown to be effective in the prevention and treatment of motion sickness 1
• Studies specifically evaluating ondansetron for seasickness found no statistically significant reduction of seasickness symptoms compared to placebo 3
• Even high-dose ondansetron did not prevent motion sickness in highly susceptible individuals 4

First-Line Recommended Treatments for Motion Sickness

• Scopolamine is considered first-line medication for prevention of motion sickness and should be administered transdermally several hours before anticipated motion exposure 1
• First-generation antihistamines, although sedating, are also effective for motion sickness prevention 1, 5
• Antihistamines are probably more effective than placebo at preventing motion sickness symptoms under natural conditions (RR 1.81,95% CI 1.23 to 2.66) 5

Behavioral Strategies for Motion Sickness

• Patients should be counseled about positioning themselves in the most stable part of the vessel 1
• Watching the true visual horizon and minimizing exposure to unpleasant motion can help reduce symptoms 1
• Lying down with eyes closed may also provide relief 1

Cautions Regarding Off-Label Use

• Using ondansetron for motion sickness represents off-label use, as it is primarily indicated for chemotherapy-induced nausea and vomiting, postoperative nausea and vomiting, and radiation-induced nausea and vomiting 2
• When prescribing medications off-label, it's important to document the clinical rationale and that standard treatments have been considered or tried 6

Alternative Antiemetic Options with Better Evidence

• Metoclopramide has been used for seasickness, but caution is warranted due to potential for serious adverse effects even with short-term, low-dose use 7
• Prochlorperazine may be considered for short-term management of severe nausea or vomiting in patients who are severely symptomatic 6

Documentation Recommendations

• When prescribing ondansetron off-label for seasickness, document:
  • The diagnosis of "Motion Sickness" (ICD-10 code T75.3)
  • That first-line therapies (scopolamine, first-generation antihistamines) were considered
  • Patient's preference for ondansetron despite limited evidence for this indication
  • Discussion of potential risks and benefits of off-label use