Sedatives/hypnotics clinical profile

Pharmacodynamics, antipsychotics also differ in their pharmacodynamics, i.e. their pharmacological and clinical profiles of action. A rough distinction is made between highly sedative, hypnotic antipsychotics (e.g. clopenthixol, levomepromazine) and other products with weaker initial sedative action (e.g. fluphenazine and haloperidol). Sedative antipsychotics are prescribed for states of major unrest, often combined with insomnia, whereas the less sedative antipsychotics are preferred for patients suffering from delusions and hallucinations but in whom heavy sedation during daytime is undesirable. 

From the published clinical studies, it would appear that the partial agonists bretazenil and abercamil are less likely to cause physiological dependence, have lower reinforcing effects and a lower incidence of subjective effects associated with abuse liability than the conventional 1,4-benzodiazepine sedative-hypnotics. It is presently unclear whether the full agonists for the GABA-A receptor, zolpidem and zopiclone, offer a real advance in the treatment of insomnia although their adverse effect profiles and abuse liability may be lower than that of the conventional benzodiazepines. 

Sedative-Hypnotics - The sedatlve-antlhlstamlne trlmeperazlne (21) at 20 mg was Inferior to nitrazepam (5 mg) as a sleep Inducer In a double-blind study.Clinical trials Indicate that zoplclone (RP-27,267, 22) Is useful as a hypnotic and is as active as nitrazepam. The compound was active In a variety of animal tests with a profile similar to the benzodiazepines. The pyrazole 2, trlazole 24a and Imidazole 24b all potentiated hexobarbltal-lnduced sleep time. 

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