Olanzapine belongs to the second-generation antipsychotic drug classification that acts as the antagonist at D2 and 5HT2A receptors. Olanzapine mechanism of action is unknown, as similar with other medications having effect in schizophrenia. Nevertheless, it has been said that this medication’s efficiency when it comes to schizophrenia is facilitated through the mixture of dopamine and serotonin type 2 antagonist. Furthermore, the mechanism of action of Olanzapine for the treatment of acute mania or bipolar disorder is also unknown.
Pharmacodynamics Of Olanzapine
The antagonism being exhibited other than 5HT2 and dopamine can explain the other therapeutic effects, as well as the side effects of Olanzapine. The antagonism of this medication to muscarinic M1-5 receptors can possibly explain its effects that mimic the effects exhibited by anticholinergic drugs. Also, its antagonism related to histamine H1 receptors can explain the drowsiness seen with this medication.
Distribution Of Olanzapine Via Oral Administration
Olanzapine is absorbed well and reaches its top efficacy within six hours after an oral administration. By first metabolism since it was taken, the medication is eliminated extensively. There is approximately 40% of the dosage metabolized prior in reaching the body’s systemic circulation. Food has no influence when it comes to the rate of the extent of the absorption of Olanzapine. In addition, this medication exhibits linear kinetics over the range of the clinical dosage.
The half-life of Olanzapine has a range of 21 to 54 hours. Its apparent plasma clearance has a range of 12 to 47 liters per hour. Daily dosage of Olanzapine has the steady-state concentrations in nearly one week that are roughly two times the potency after single dosages. The half-life, concentrations of plasma and clearance of this medication may vary among users on factors such as age, gender and smoking status. Olanzapine is likewise widely distributed all throughout the body. The distribution volume is nearly 1000 liters.
Administration Of Olanzapine Via Intramuscular Route
The administration of Olanzapine via the intramuscular route results in the quick absorption with associated peak concentrations of plasma within 15 to 45 minutes. A five-milligram dose of Olanzapine for injection produces an optimum plasma concentration of nearly five times more effective than the plasma concentration produced via oral administration, based on the studies in healthy volunteers.
However, the half-life after the intramuscular injection is the same to that of the oral dosage. The pharmacokinetics are also linear over the range of the clinical dosing. In addition, the metabolic profiles following the administration of the intramuscular injection are similar to the metabolic profiles following the oral administration of Olanzapine.