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phenothiazines

phenothiazines

Introduction

  • closely related to tricyclic antidepressants chemically.
  • 2 main sub-groups:
      • low clinical potency
      • medium extrapyramidal toxicity
      • high sedative actions
      • high hypotensive actions
    • piperazine (eg. fluphenazine)
      • high clinical potency
      • high extrapyramidal toxicity
      • low sedative action
      • very low hypotensive actions
  • Their actions primarily appear to be related to central D2 antagonism but they also have antagonistic actions on the following receptors:
    • alpha1 adrenergic ⇒ hypotension
    • muscarinic ⇒ anticholinergic
    • 5HT2
    • D1 ⇒ extrapyramidal, dystonic reactions, neuroleptic malignant syndrome
    • H1 (some only have this action - those with shorter side chains)
    • quinidine-like (only thioridazine & mesoridazine) ⇒ prolonged QTc & risk of VT
    • actions on the chemo-receptor trigger zone (CTZ) ⇒ anti-emetic
    • lowered seizure threshold
phenothiazines.txt · Last modified: 2009/05/01 10:13 (external edit)