Which medications in the drug class Antiemetic Agents 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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Antiemetic Agents

The vomiting center (VC) of the central nervous system (CNS) may be stimulated directly by gastrointestinal (GI) irritation, motion sickness, or vestibular neuritis. Increased activity of central neurotransmitters, such as dopamine in the chemoreceptor trigger zone (CTZ) or acetylcholine in the VC, appear to be major mediators of vomiting.

An emetogenic episode may initiate the release of serotonin (5-HT) from enterochromaffin cells in the GI tract. 5-HT then binds to 5-HT3 receptors, which stimulate vagal neurons that transmit signals to the VC, resulting in nausea and vomiting. Pharmacologic agents are directed to the particular etiology or mechanism that stimulates the vomiting response.

Ondansetron (Zofran)

The 5-HT3 antagonist ondansetron directly acts at the CTZ and vagal afferents from the GI tract. It attenuates or, occasionally, aborts an active episode of CVS. High doses are more effective in patients with CVS.

Promethazine (Phenergan, Phenadoz)

Promethazine is a phenothiazine derivative that possesses antihistaminic, sedative, antimotion sickness, antiemetic, and anticholinergic effects.

Prochlorperazine (Compro)

Prochlorperazine may relieve nausea and vomiting by blocking postsynaptic mesolimbic dopamine receptors through its anticholinergic effects and depressing the reticular activating system.

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