H1-antagonists, also known as H1 receptor antagonists or antihistamines, are a class of drugs that block the action of histamine at the H1 receptors. The body produces histamine, a natural substance that plays a key role in various physiological processes, especially in immune responses and allergic reactions.
Ethylene diamine derivatives
Ethylene diamine derivatives, characterized by a unique chemical structure, hold significant pharmacological potential in the realm of antihistamine drugs. They promise to address allergic reactions, with their distinct chemical makeup contributing to efficacy. This overview explores their application in antihistamine medications, emphasizing their pivotal role in mitigating histamine effects and their potential impact on allergic conditions.
Metabolism of ethylene diamine derivatives:
These antihistaminic drugs undergo N-demethylation and subsequent deamination. In addition, some compounds produce quaternary N-glucuronide as urinary metabolites, a process that occurs to some extent in many relatively unhindered tertiary aliphatic amines among the antihistamines and also in other liphophilic tertiary aliphatic amine drugs.
i. Tripelennamine (Pyribenzamine HCl)
Mechanism of Action:
Tripelennamine interacts with the histamine H1 receptor, inhibiting the activity of naturally occurring histamine. This inhibition results in the temporary alleviation of adverse symptoms induced by histamine.
Properties and uses:
Tripelennamine, the first ethylenediamine developed in American laboratories, is a white, crystalline powder that dissolves in water and is freely soluble in alcohol and ether but remains insoluble in chloroform or benzene. Considered equally effective as diphenhydramine, it offers potential advantages of fewer and less severe side reactions. Tripelennamine treats allergic rhinitis, conjunctivitis, angioedema, dermographism, and anaphylactic reactions.
Dose:
The usual dose is 25–50 mg for adults consumed orally four to six times daily.