Antihistamines antidepressants derived from

Tricyclic Antidepressants. Imipramine [50-49-7] (32), which was the first tricycHc antidepressant to be developed, is one of many useful psychoactive compounds derived from systematic molecular modifications of the antihistamine prometha2ine [60-87-7] (see Histamine and histamine antagonists). The sulfur atom of prometha2ine was replaced with an ethylene bridge and the dimethylamino group attached to an / -propyl group, rather than to an isopropyl one, of the side chain. The actual synthesis of (32) is typical of the compounds in this class (37). 

As a consequence, several drugs have been developed by enhancing the side effect of another drug. For example, the mood-improving effect of iproniazid was discovered when it was tested as an antituberculous drug antidepressant inhibitors of neurotransmitter reuptake, like imipramine and desipramine, stem from the antipsychotic dopamine antagonist chlorpromazine, which itself was derived from Hi antihistaminics [35,36,51]. 

Historically, both the tricyclic antipsychotic and antidepressant agents are derived in almost direct line from a series of tricyclic antihistaminic compounds (see 104 below). Minor changes in structure in some of the newer... 

The antidepressant drugs were derived via the process of molecular modification from the sympathomimetic agents, antihistamines, antispasmodics (anticholinergics), tranquilizers, and tuberculostatic agents. 

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