Interactions Interfering with Central Adrenoreceptor Activity and Hypotension of Centrally Acting Antihypertensive Agents

Abstract

This chapter discusses interactions interfering with central adrenoreceptor activity and hypotension of centrally acting anti hypertensive agents. The interference of centrally acting antihypertensive drugs and various psychotropic drugs is mainly studied in cats. In chloralose-anesthetized cats the centrally induced hypotensive effect of clonidine, and in some cases α-methyl-DOPA, is diminished upon pretreatment with a variety of tricyclic antidepressants and phenothiazineneuroleptics. This phenomenon could be confirmed by experiments in spontaneously hypertensive rats. Haloperidol is hardly effective, whereas pimozide and benzodiazepine tranquillizers do not diminish the hypotensive response to clonidine. The interaction probably occurs at the level of the central α-adrenoreceptors located in the brain stem. The lack of interaction with pimozide or the benzodiazepine tranquillizers is explained in the chapter by the fact that these drugs are not α-blockers.