Haloperidol, antiemetic action

Antiemetics that act on the vomiting centre have antimuscarinic (their principal mode) and anti-histaminic action (hyoscine, promethazine) they alleviate vomiting from any cause. In contrast, drugs that act on the CTZ (haloperidol, ondansetron) are effective only for vomiting mediated by stimulation of the chemoreceptors (by morphine, digoxin, cytotoxics, uraemia). The most efficacious drugs act at more than one site (Table 31.1). 

Haloperidol blocks dopamine receptors in the brain and hence produces a very high incidence of movement disorders such as parkinsonism (see phenothiazine derivatives). Its mechanism of action in Gilles de la Tourette s syndrome is unknown. In addition to blocking dopamine receptors, haloperidol has many other central and peripheral effects it has weak peripheral anticholinergic and antiemetic... 

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