Pimozid

The role of fluonne in the development of CNS agents has been reviewed [14] Ruonnated phenothiazines, typified by fluphenazine (7[Pg.1121]

C4H5CIO 4023-34-1) see Buprenorphine Fexofenadine hydrochloride Naltrexone Prazepam cyclopropanecarboxylic acid ethyl ester (C(,H o02 4606-07-9) see Pimozide... 

Kjellberg, B., and Randrup, A. The effects of amphetamine and pimozide, a neuroleptie, on the social behaviour of vervet monkeys (Cercopithecus sp.). In Vinar, 0. Votaya. Z. and Bradley, P.B., eds. Advances in Neuropsychopharmacology. Amsterdam-London North Holland Publishing Co., 1971. pp. 305-310. 

DeWit, H., and Wise, R.A. Blockade of cocaine reinforcement in rats with the dopamine receptor blocker pimozide, but not with the noradrenergic blockers phentolamine and phenoxybenzamine. Can J Psychol 31 195-203, 1977. 

Yokel, R.A., and Wise, R.A. Increased lever pressing for amphetamine after pimozide in rats Implications for a dopamine theory of reward. Science 187 547-549, 1975. 

The administration of low doses of PCP to rodents induces hyperactivity and stereotypy (Chen et al. 1959 ). The observation that neuroleptics such as chlorpromazine, haloperidol, and pimozide, and adrenolytics such as alpha-methyl paratyrosine antagonize these behavioral effects of PCP suggests that they are mediated by facilitation of central dopaminergic neurotransmission (Murray and Horita 1979). The actions of PCP on central dopaminergic neurotransmission may be similar to amphetamine. A dose of PCP (2.5 mg/kg) in rats, which has no effects when given alone, enhances the behavioral effects of 1 and 3 mg/kg of d-amphetamine (Balster and Chait 1978). PCP, like dopamine, has also been shown to suppress plasma prolactin (Bayorh et al. 1983). However, the firm establishment of an excl usive relationship between dopamine neuro-transmission and PCP effects is difficult because of the prominent interactions of this drug with other neurotransmitter systems. 

High-potency antipsychotics include haloperidol, fluphenazine, thiothixine, and pimozide. 

The answer is b. (Katzung, p 4822) Haloperidol, a butyrophenone, is by far the most likely antipsychotic to produce extrapyramidal toxicides Other agents, such as piperazine (an aromatic phenothiazine), thiothixene (a thioxanthene), and pimozide (a diphenylbutyropiperidine) are comparitively less likely to produce extrapyramidal toxicity than haloperi-dol. The antagonism of dopamine in the nigrostriatal system might explain the Parkinson-like effects Both haloperidol and pimozide act mainly on D2 receptors, whereas thioridazine and piperazine act on ooadrenergie receptors, and have a less potent but definite effect on D2 receptors. 

The answer is d. (Hardman, p 420. Katzung, p 4852) Tourette s syndrome is effectively treated with haloperidol, a high-potency antipsychotic. If patients are unresponsive or do not tolerate haloperidol, they might be switched to pimozide. 

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