Fast-Off эффект

"Mode of Action

Quetiapine binds to a number of potentially relevant neurotransmitter receptors. Quetiapine has a greater affinity for serotonin 5HT2 receptors than for dopamine D, receptors. Together with considerable activity at histamine receptors and a-adrenoceptors, that explains somnolence and orthostatic hypotension caused by it. Quetiapine has less affinity for dopamine D2 receptors than dopamine itself, as a result It is rapidly dissociated from D2 receptor which results into several beneficial effects such as absence of EPS, absence of tardive dyskinesia and no effect on serum prolactin levels. This phenomena is known as "Fast-off",

Fast – off Effect

Typical antipsychotic drugs such as haloperidol, chlorpromazine, and fluphenazine have higher affinity for D2 receptor and bind more tightly than dopamine itself to D2 receptors. Prolonged occupancy of D2 receptors by typical antipsychotic drug result into several side effects such as extrapyramidal symptoms, elevated levels of serum prolactin and after a period of time tardive dyskinesia. It has been demonstrated that haloperidol, chlorpromazine dissociate very slowly over a 30 minutes time span, while quetiapine and clozapine dissociate rapidly from D2 receptors in less than 60 seconds.¹²"

Quetiapine: A Novel Anti Schizophrenic Drug