Drafzin Mechanism of Action

Pharmacology: The anti-depressant, antiobsessional, and antibulimic actions of fluoxetine are presumed to be linked to its ability to inhibit the neuronal reuptake of serotonin. It selectively inhibits serotonin reuptake in synaptic nerve terminals.
Pharmacokinetics: Fluoxetine is well absorbed after oral administration (85%). Peak concentrations in the plasma are achieved within approximately 6 hours after the administration. Food does not affect the amount of fluoxetine absorbed, but the peak concentration is obtained slightly later. Norfluoxetine is the main metabolite being the result of demethylisation and is also a selective serotonin reuptake inhibitor. The half-live of fluoxetine and norfluoxetine vary individually from 2-3 days and 7-9 days, respectively. Owing to the long half-life steady state is achieved within 2-3 weeks. The plasma clearance in patients is reported to be 20 L/hour for fluoxetine and 9 L/hour for norfluoxetine. The drug is totally excreted 3-5 weeks after discontinuation of the therapy. The volume distribution for fluoxetine and norfluoxetine is about 20-45 L/kg and binding to plasma proteins is about 94%.
Fluoxetine undergoes extensive metabolism and it metabolites are excreted mainly renally and only to a small amount biliary.