What are the recommended medications and dosages for treating motion sickness?

Recommended Medications for Motion Sickness

For prevention of motion sickness, transdermal scopolamine is the first-line medication, applied as a patch behind the ear at least 4-6 hours before travel, delivering 1 mg over 3 days. 1, 2

First-Line Options

Transdermal Scopolamine

• Dosage: One patch (1.5 mg total, delivering 1 mg over 3 days)
• Timing: Apply at least 4-6 hours (ideally 8-12 hours) before travel
• Application: Place on hairless area behind one ear
• Duration: Effective for up to 3 days; if longer protection needed, remove and apply new patch behind opposite ear
• Efficacy: Reduces motion sickness incidence by 60-80% 3
• Advantages: Long duration of action, less sedating than antihistamines
• Common side effects: Dry mouth (50-60%), drowsiness (up to 20%), blurred vision 1, 3

First-Generation Antihistamines

Dimenhydrinate

• Dosage: 50 mg every 4-6 hours
• Timing: Take 30-60 minutes before travel
• Maximum daily dose: 400 mg
• Efficacy: Similar to or less effective than scopolamine 3, 4
• Side effects: Higher incidence of sedation than scopolamine 3

Meclizine

• Dosage: 25-50 mg once daily
• Timing: Take 1 hour before travel
• Duration: Effects last 12-24 hours
• Side effects: Drowsiness, dry mouth

Second-Line Options

Combination Therapy

For faster onset of protection:

• Transdermal scopolamine patch applied 1 hour before travel PLUS
• Oral scopolamine (0.3-0.6 mg) 3

Other Antihistamines

• Diphenhydramine: 25-50 mg every 4-6 hours
• Promethazine: 25 mg every 4-6 hours (can be combined with ephedrine)

Ineffective Treatments

The following have been shown to be ineffective for motion sickness and should not be used:

• Ondansetron and other 5-HT3 antagonists 2, 5
• Non-sedating antihistamines 2
• Ginger root 2

Treatment Algorithm

1. Assess patient risk factors:

   • History of motion sickness
   • Age (children and elderly may be more sensitive to side effects)
   • Planned duration of travel
   • Ability to tolerate sedation

2. For short trips (<6 hours):

   • First-generation antihistamines (dimenhydrinate or meclizine)

3. For longer trips (>6 hours):

   • Transdermal scopolamine patch

4. For patients with severe motion sickness history:

   • Consider combination therapy with transdermal scopolamine plus oral antihistamine

5. For patients concerned about sedation:

   • Transdermal scopolamine (less sedating than antihistamines)

Important Considerations

• Contraindications for scopolamine: Angle closure glaucoma, hypersensitivity to belladonna alkaloids 1
• Monitor for neuropsychiatric effects: Scopolamine can cause confusion, disorientation, and rarely hallucinations or psychosis, especially in elderly patients 1
• Pregnancy considerations: Scopolamine is typically not recommended during pregnancy 6
• Breastfeeding: Scopolamine is not recommended during breastfeeding 6
• Elderly patients: Use lower doses due to increased sensitivity to side effects 7

Non-Pharmacological Approaches

While medications are effective, also advise patients to:

• Position themselves in the most stable part of the vehicle (front seat in car, mid-ship on boats)
• Focus on the horizon
• Avoid reading or using electronic devices
• Minimize head movements
• Ensure adequate ventilation

Remember that early prevention is more effective than treating established symptoms of motion sickness, as medications are primarily preventive rather than therapeutic once symptoms develop 2.