Pharmacological Classification: Antipsychotic.
Pharmacology: Pharmacodynamics: OLANZAPINE (OLAVEX 5/10) an atypical antipsychotic agent, is used to treat both negative and positive symptoms of schizophrenia, acute mania with bipolar disorder, agitation, and psychotic symptoms in dementia. Future uses may include the treatment of obsessive-compulsive disorder and severe behavioral disorders in autism. Structurally and pharmacologically similar to clozapine, olanzapine binds to alpha(1), dopamine, histamine H1, muscarinic, and serotonin type 2 (5-HT2) receptors.
Mechanism of Action: The mechanism of action of olanzapine, as with other drugs having efficacy in schizophrenia, is unknown. However, it has been proposed that this drug's efficacy in schizophrenia is mediated through a combination of dopamine and serotonin type 2 (5HT2) antagonism. The mechanism of action of olanzapine in the treatment of acute manic or mixed episodes associated with bipolar I disorder is unknown.
Pharmacokinetics: Absorption: Readily absorbed orally and IM. C max is approximately 6 h (oral) and 15 to 45 min (short-acting injection). Steady state is approximately 1 wk (oral). Food does not affect the rate or extent of oral olanzapine absorption.
Distribution: Extensively distributed throughout the body. Vd is approximately 1,000 L; 93% is protein bound.
Metabolism: In liver by glucuronidation and CYP-450-mediated oxidation; major circulating metabolites are inactive.
Elimination: Elimination is 57% in urine (7% unchanged); 30% eliminated in feces. The half-life is 21 to 54 h (oral, short-acting injection) and 30 days (ER injection). Plasma Cl is 12 to 47 L/h.