What medications are used to treat motion sickness?

Medications for Motion Sickness

Scopolamine transdermal patches are the first-line medication for prevention of motion sickness, followed by first-generation antihistamines such as meclizine, dimenhydrinate, and diphenhydramine. 1, 2

First-Line Options

1. Scopolamine (Transdermal)

• Mechanism: Anticholinergic that blocks acetylcholine, reducing neural mismatching that causes motion sickness 2
• Dosing: Apply one patch (1.5 mg) behind the ear at least 4 hours before travel; effective for up to 3 days 1
• Advantages: Most effective preventive medication with longest duration of action 3
• Cautions:
  • May cause drowsiness, disorientation, blurred vision
  • Contraindicated in angle-closure glaucoma 1
  • Should not be used with alcohol or when operating machinery 1

2. First-Generation Antihistamines

These medications have a suppressive effect on the central emetic center to relieve nausea and vomiting 2:

• Meclizine (Antivert, Bonine)

  • Dosing: 12.5-25 mg three times daily 2
  • Less sedating than other antihistamines

• Dimenhydrinate (Dramamine)

  • Dosing: 25-50 mg three times daily 2
  • Take 30-60 minutes before travel

• Diphenhydramine (Benadryl)

  • Dosing: 12.5-25 mg three times daily 2
  • Most sedating option

Second-Line Options

1. Promethazine

• Phenothiazine with antihistamine properties
• Particularly effective for severe nausea and vomiting 2

2. Benzodiazepines

• Can reduce subjective sensation of spinning
• Examples: diazepam, clonazepam
• Caution: Can interfere with central compensation and cause dependence 2

Ineffective Medications

• Ondansetron (Zofran): Despite its effectiveness for other types of nausea, research shows it is not effective for motion sickness 4, 5
• Non-sedating antihistamines: Second-generation antihistamines are not effective for motion sickness 5
• Ginger: While sometimes recommended, evidence does not support its effectiveness for motion sickness 5

Medication Selection Algorithm

1. For planned travel with high risk of motion sickness:

   • First choice: Scopolamine patch applied 4 hours before travel
   • Alternative (if scopolamine contraindicated): Meclizine 25 mg 1 hour before travel

2. For unexpected motion exposure or shorter trips:

   • First choice: Meclizine 25 mg or dimenhydrinate 50 mg
   • For nighttime travel: Diphenhydramine 25 mg (when sedation is not a concern)

3. For severe symptoms or those who failed other treatments:

   • Consider combination therapy (antihistamine plus scopolamine) under medical supervision

Important Considerations

• Timing is critical: All medications work better for prevention than treatment of established symptoms 6, 3
• Sedation risk: Most effective motion sickness medications cause some degree of sedation 6
• Children: Dosing must be carefully calculated by weight; avoid scopolamine in young children 1
• Pregnancy: Use caution with all motion sickness medications during pregnancy

Non-Pharmacological Approaches

When medications cannot be used or as adjuncts:

• Position in the most stable part of the vehicle (front seat in car, mid-ship on boat)
• Focus on the horizon or a fixed point
• Avoid reading or using electronic devices
• Minimize head movements
• Ensure adequate ventilation
• Gradual, controlled exposure to motion can help develop tolerance 5, 7

Remember that prevention is more effective than treatment once symptoms have developed. For best results, medications should be taken before exposure to motion.