Tolanz 5/Tolanz 10 Mechanism of Action

Pharmacology: Pharmacodynamics: Mechanism of Action: Olanzapine is a thienobenzodiazepine atypical antipsychotic. It has affinity for serotonin, muscarinic, histamine H-1, and adrenergic (α1) receptors as well as various dopamine receptors.
Pharmacokinetics: Olanzapine is well absorbed from the gastrointestinal tract after oral administration but undergoes considerable first-pass metabolism. Peak plasma concentrations are achieved about 5 to 8 hours after oral administration and about 15 to 45 minutes after intramuscular administration. Olanzapine is about 93% bound to plasma proteins. It is extensively metabolized in the liver primarily by direct glucuronidation and by oxidation mediated through the cytochrome P450 isoenzymes CYP1A2 and, to a lesser extent, CYP2D6. The two major metabolites 10-N-glucuronide and 4'-N-desmethyl olanzapine appear to be inactive. About 57% of a dose is excreted in the urine, mainly as metabolites and about 30% appears in the feces. The plasma elimination half-life has been variously reported to be about 30 to 38 hours; half-lives tend to be longer in female than in male patients. Olanzapine is distributed into the breast milk.