What are the recommended medications for preventing and managing motion sickness in healthy adults and adolescents?

Medications for Motion Sickness Prevention and Management

For preventing motion sickness in healthy adults and adolescents, use scopolamine transdermal patch as first-line therapy, applied 6-8 hours before travel, or alternatively use meclizine 25 mg orally 1 hour before departure if scopolamine is contraindicated. 1

First-Line Prevention: Scopolamine

Scopolamine is the most effective first-line medication for motion sickness prevention and should be administered as a 1.5 mg transdermal patch placed behind the ear at least 6-8 hours before anticipated motion exposure, with each patch providing protection for approximately 3 days. 1, 2 Scopolamine works by blocking acetylcholine, a widespread CNS neurotransmitter, thereby reducing the neural mismatch that causes motion sickness. 1

• Scopolamine is more effective than placebo in preventing motion sickness symptoms under natural conditions. 3, 4
• The transdermal formulation provides sustained drug delivery and avoids gastrointestinal absorption issues. 2
• Scopolamine is superior to methscopolamine and equivalent to antihistamines as a preventative agent. 3

Common Side Effects of Scopolamine

• Dry mouth is the most common adverse effect, occurring more frequently than with other agents. 3, 4
• Drowsiness, blurred vision, and dizziness occur at rates similar to other motion sickness medications. 3
• Rare ocular adverse effects such as postoperative glare or diplopia have been reported with transdermal patches. 1

Second-Line Prevention: Antihistamines

If scopolamine is contraindicated or causes intolerable side effects, use meclizine 12.5-25 mg orally three times daily, starting 1 hour before travel. 1, 2 Antihistamines suppress the central emetic center to relieve nausea and vomiting, with approximately 40% effectiveness in preventing symptoms under natural conditions. 1

• First-generation antihistamines (meclizine, dimenhydrinate, cinnarizine) are probably more effective than placebo at preventing motion sickness symptoms under natural conditions (40% prevention with antihistamines versus 25% with placebo). 5
• Antihistamines may be more likely to cause sedation compared to placebo (66% versus 44%). 5
• Antihistamines result in little or no difference in blurred vision or impaired cognition compared to placebo. 5

Specific Antihistamine Options

• Meclizine: 12.5-25 mg orally three times daily, most commonly used antihistamine for motion sickness. 1, 6
• Dimenhydrinate: Alternative first-generation antihistamine with similar efficacy to meclizine. 6, 5
• Cinnarizine: Effective first-generation antihistamine, though less commonly available in some countries. 5

Important: Second-generation nonsedating antihistamines are NOT effective for motion sickness prevention. 2

Combination Therapy for Severe Cases

For severe motion sickness requiring combination therapy, use scopolamine transdermal patch plus meclizine together, providing complementary anticholinergic and antihistaminic mechanisms of action. 1 This approach is reserved for patients with particularly severe symptoms or those who have failed monotherapy.

Treatment of Established Symptoms

For acute nausea and vomiting once motion sickness has developed, use promethazine 12.5-25 mg orally or intramuscularly for rapid symptom control. 1 Promethazine is a phenothiazine with antihistamine properties that provides potent antiemetic effects. 1

• Promethazine has side effects including hypotension, respiratory depression, neuroleptic malignant syndrome, and extrapyramidal effects, so it should be reserved for severe cases. 1
• No randomized controlled trials have examined scopolamine's effectiveness in treating established motion sickness symptoms—it is only proven for prevention. 3, 4

Special Population Considerations

Adolescents (12-17 years)

• Multiple NSAIDs and triptans have been approved for migraine in this age group, but for motion sickness specifically, use meclizine or scopolamine with the same dosing as adults. 7
• Domperidone can be used for nausea in adolescents aged 12-17 years. 7

Elderly Patients

Initiate scopolamine or meclizine at reduced doses and titrate cautiously in older adults to lower the risk of anticholinergic adverse events such as falls and cognitive impairment. 1 Anticholinergic medications are an independent risk factor for falls in the elderly. 1, 8

• Monitor elderly patients closely for anticholinergic side effects. 1
• Avoid prescribing multiple anticholinergic agents concurrently because cumulative anticholinergic burden markedly increases fall risk. 1
• Review all medications for potential drug-drug interactions before adding vestibular suppressants. 8

Pregnant Women

• Paracetamol (acetaminophen) should be used as first-line medication despite poor efficacy. 7
• Metoclopramide can be used for nausea associated with motion sickness in pregnancy. 7
• Scopolamine and antihistamines should be avoided during pregnancy unless benefits clearly outweigh risks. 7

Breastfeeding Women

• Scopolamine passes into breast milk, so consider interrupting breastfeeding or selecting alternative medication. 1
• Ibuprofen is considered safe during breastfeeding. 7

Absolute Contraindications for Scopolamine

Scopolamine should be omitted entirely in individuals with glaucoma, urinary retention, or severe prostatic hypertrophy due to risk of exacerbating these conditions. 1

• Concomitant use of over-the-counter decongestants, cold/flu remedies, allergy medications, sleep aids, or psychoactive drugs with anticholinergic properties can compound side effects. 1
• Patients with CNS depression or those using adrenergic blockers should use scopolamine with caution. 8

Medications to Avoid

Do NOT use the following for motion sickness:

• Ondansetron and other 5-HT3 antagonists: Not effective for motion sickness prevention or treatment. 2
• Ginger root: Not effective in prevention and treatment of motion sickness. 2
• Nonsedating antihistamines (loratadine, cetirizine, fexofenadine): Ineffective for motion sickness. 2
• Benzodiazepines: Not recommended due to lack of efficacy and significant harm potential. 1
• Betahistine: Showed no significant benefit over placebo in reducing symptoms. 8

Critical Timing Considerations

• Scopolamine patch: Apply 6-8 hours before anticipated motion exposure for optimal effectiveness. 1, 2
• Meclizine: Take 1 hour before travel. 2
• All preventive medications work best when taken BEFORE symptoms develop—once nausea and vomiting are established, oral medications are poorly absorbed. 6

Duration of Use

Vestibular suppressant medications should not be used for long-term management, as they can interfere with central vestibular compensation in peripheral vestibular conditions. 1, 8 Limit use to the duration of motion exposure plus 24-48 hours if needed for residual symptoms.

Practical Algorithm

1. For routine prevention in healthy adults/adolescents: Apply scopolamine patch 6-8 hours before travel. 1, 2

2. If scopolamine contraindicated or unavailable: Use meclizine 25 mg orally 1 hour before travel, repeat every 8 hours as needed. 1, 2

3. For severe anticipated symptoms: Combine scopolamine patch with meclizine 12.5-25 mg three times daily. 1

4. For established nausea/vomiting: Use promethazine 12.5-25 mg orally or IM for rapid control. 1

5. Always combine medications with behavioral modifications: Position in stable part of vehicle, watch horizon, minimize head movements, ensure adequate ventilation. 6, 2