Quetaz Mechanism of Action

Pharmacology: Pharmacodynamics: Quetiapine fumarate is a psychotropic agent belonging to a chemical class, the dibenzothiapine derivatives. The chemical name is 2-[2-(4-dibenzo [b,f] [1,4]thiazepin-11-yl-1-piperazinyl) ethoxy]-ethanol fumarate (2:1) (salt). It has an empirical formula of C₄₂H₅₀N₆O₄S₂.C₄H₄O₄.
Quetiapine is an antagonist at multiple neurotransmitter receptors in the brain: Serotonin 5-HT1A and 5-HT2, dopamine D1 and D2, histamine H1, adrenergic α1 and α2 receptors. Quetiapine has no appreciable affinity at cholinergic muscarinic and benzodiazepine receptors.
Quetiapine blocks the action of dopamine agonists, measured either behaviorally or electrophysiologically, and elevates dopamine metabolite concentrations, a neurochemical index of D2-receptor blockade.
Pharmacokinetics: Absorption: Quetiapine fumarate is rapidly absorbed after oral administration and throughout the body, reaching peak plasma concentration in 1.5 hours.
Distribution: Quetiapine is widely distributed throughout the body. It is about 83% bound to plasma protein.
Metabolism: Quetiapine is extensively metabolized by the liver. The major metabolic pathways are sulfoxidation to the sulfoxide metabolite and oxidation to the parent acid metabolite; both metabolites are pharmacologically inactive. In vitro studies using human liver microsomes revealed that the cytochrome P450 3A4 isoenzyme is involved in the metabolism of quetiapine to its major, but inactive, sulfoxide metabolite and in the metabolism of its active metabolite N-desalkyl quetiapine.
Elimination: Following a single oral dose of 14C-quetiapine, less than 1% of the administered dose was excreted as unchanged drug, indicating that quetiapine is highly metabolized. Approximately 73% and 20% of the dose was recovered in the urine and feces, respectively.