Piperazine neuroleptic drugs

As previously noted (SEDA-4, 21 SEDA-5, 17), amoxapine has a tricyclic nucleus with a modified piperazine side chain and is closely related to the neuroleptic drug loxapine. In animals, amoxapine has no antisero-tonergic properties and less anticholinergic activity than prototype drugs. Peak plasma concentrations are achieved in less than 2 hours, and the half-lives of the parent drug and its two active metabolites are 8, 6, and 30 hours respectively. 

It has been suggested that the less potent sedative neuroleptic drugs (aliphatic or piperidine phenothiazines) lower the convulsive threshold more than the potent neuroleptic drugs (piperazine phenothiazines) (170). Variable and unpredictable effects on seizure activity related to butyrophenones have been reported (171). 

Figure 12-20. Relationship of piperazine-type drug to neuroleptic receptor. Phenothiazine in boat -shaped projection.

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