Phenothiazine antiemetics are a type of medicine that may be used to relieve nausea and vomiting. They work by inhibiting dopamine, muscarinic and histamine (H1) receptors generally in the vomiting center and chemoreceptor trigger zone.
Phenothiazine antiemetics are usually reserved for severe cases of nausea and vomiting that occur as a result of chemotherapy or radiotherapy. Drowsiness and extrapyramidal side effects (unusual movement disorders) are common side effects. Some phenothiazine antiemetics are also used in the treatment of psychosis and schizophrenia.