​Pharmacology - Promethazine

​Pharmacology - Promethazine 
Promethazine has an anticholinergic action, some local anesthetic action, weak adrenoceptor antagonism, and a fairly pronounced sedative effect. It also inhibits the actions of H1-receptors, which results in a reduction in the acute hypersensivity reactions.

Mode of Action 
Competitive inhibitor of histamine at H1 receptors on smooth muscle, among other applications

It is administered orally, through a deep intramuscular injection, or with a gradual intravenous infusion; it penetrates the central nervous system.

Use in Clinical Settings 
Some examples of hypersensitivity reactions include hay fever and urticaria, as well as premedication, sedation, emergency treatment for anaphylaxis, and motion sickness.

Adverse Effects 
Dry mouth, sometimes blurred vision, constipation, and urine retention are symptoms of anticholinergic activity on peripheral muscarinic receptors. Other symptoms include headaches and tiredness.