First-line medication for prevention; transdermal formulation available by prescription; oral formulation not available in the United States; causes more dry eyes and dry mouth than antihistamines, but less sedation; may double dose or combine with antihistamines, or combine oral and transdermal formulations (increased risk of side effects); use with caution in older patients; not recommended for children younger than 10 years

Common: dry eyes, dry mouth, sensitivity to bright light

Less common: blurred vision, dizziness, headache, sedation

Uncommon: acute angle glaucoma, confusion, contact dermatitis, monocular pupillary dilation urinary retention

Adults and children older than 12 years: 30 mg two hours before travel, then 15 mg every eight hours as needed

Children five to 12 years of age: 15 mg two hours before travel, then 7.5 to 15 mg every eight hours as needed

Available over the counter in Mexico and Europe; not available in the United States or Canada; has calcium channel–blocking properties

Class effects

Very common: sedation

Common: dry eyes, dry mouth

Less common: blurred vision, sensitivity to bright light

Uncommon: confusion, urinary retention

Adults and children older than 12 years: 50 mg one hour before travel, then every four to six hours as needed (maximum: 200 mg per day)

Children six to 11 years of age: 25 mg one hour before travel, then every six to eight hours as needed (maximum: 75 mg per day)

Available over the counter

Adults and children older than 12 years: 50 to 100 mg every four to six hours (maximum: 400 mg per day)

Children six to 12 years of age: 25 to 50 mg every six to eight hours as needed (maximum: 150 mg per day)

Available over the counter

Adults and children older than 12 years: 25 to 50 mg every four to six hours (maximum: 300 mg per day)

Children six to 12 years of age: 12.5 to 25 mg every four to six hours as needed (maximum: 150 mg per day)

Oral formulations available over the counter; solution for intramuscular administration available by prescription

Adults: 25 mg 30 to 60 minutes before travel, then every 12 hours as needed

Children: 12.5 to 25 mg twice daily as needed

Prescription only; also available as rectal suppositories and as solution for intramuscular injection

Adults and children 12 years and older: 25 to 50 mg one hour before travel, then every 24 hours as needed

Children younger than 12 years: not recommended

Available over the counter