Promethazine hydrochloride, also known as phenazine, is a commonly used phenothiazine antihistamine in clinical practice. Although its adverse reactions are not uncommon in clinical reports, it is still widely used in primary hospitals due to its clear effect and low price. use.
Promethazine hydrochloride is the earliest discovered tricyclic antihistamine with a phenothiazine structure. It has anti-tussive effect. It can competitively block histamine H1 receptors to produce antihistamines and counteract the capillary caused by histamine. The blood vessels dilate and reduce their permeability. Therefore, the cough caused by the irritation of the trachea can be calmed down.