Which medications in the drug class Antihistamines, 1st Generation are used in the treatment of Cyclic Vomiting Syndrome?

Updated: Oct 31, 2018
  • Author: Thangam Venkatesan, MD; Chief Editor: Carmen Cuffari, MD  more...
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Antihistamines, 1st Generation

Antihistamines may be used to prevent nausea rather than treating vomiting, though antihistamines appear to be the best of all classes in treating it once it has begun. Their effectiveness is likely due to their central anticholinergic properties that reduce activity in the vestibular nuclei. The nonsedating antihistamines (ie, those that do not cross the blood-brain barrier) do not appear to be effective in either preventing or treating nausea and vomiting. Common adverse effects can include dry mouth/nose/throat, drowsiness, and sensitivity to bright light (secondary to mydriasis). Less common adverse effects include palpitations, urinary retention, bloating, constipation, headache, and confusion. They should be taken 1 hour prior to departure.


Cyproheptadine is a nonselective antihistamine effective against CVS and migraines. It is also an appetite stimulant. Therapeutic effects are observed within 1-2 weeks. This agent is an excellent choice for children younger than 5 years.

Diphenhydramine (Benadryl)

Diphenhydramine is used for treatment and prophylaxis of vestibular disorders that may cause nausea and vomiting. It provides mild sedation, as well as antinausea and antiemetic actions synergistic with those of 5-HT3 antagonists.

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