Olanzapine: Everything You Need To Know
Olanzapine is a drug that belongs to the family of atypical antipsychotics. It is indicated for the treatment of schizophrenia, as well as to treat depressive episodes associated with bipolar disorder and episodes of mania.
The olanzapine formulations were manufactured and distributed by the pharmaceutical company Eli Lilly and Company. The patent for this drug expired in 2011, and since then it has been marketed as a generic worldwide.
Learning about schizophrenia
Schizophrenia is a chronic psychiatric disorder characterized by distorted thoughts, hallucinations or delusions. These three symptoms are known clinically as the “positive” symptoms. However, a patient may also suffer from another series of symptoms, the “negative” ones. Among them we find:
- Social isolation.
- Apathy.
- Decreased emotional response.
Regarding the causes that trigger this disease, schizophrenia results from a set of factors that predispose the patient to develop it. Among the main factors we can mention:
- Biochemical alterations in the brain : people with this disease have altered levels of dopamine and serotonin in the brain.
- Genetic factors : the presence of the disease in the parents or close relatives is a factor that increases the probability of its appearance in the child.
- Problems in pregnancy : complications such as anoxia, infections or some trauma during this period can affect the baby, favoring the appearance of this psychiatric disease, as well as other problems.
Structure and mechanism of action: how does it exert the effect on the body?
This antipsychotic has a chemical structure related to benzodiazepines. Specifically, it is structurally related to quetiapine and clozapine. Its antipsychotic activity is justified by interacting with serotonin receptors. More specifically, it blocks 5-HT2 receptors for serotonin in the brain.
Furthermore, it also interacts with dopamine D1 and D2 receptors, but with a more moderate affinity. It has a certain affinity for muscarinic cholinergic, alpha-adrenergic and H1 histamine receptors.
Due to all these interactions, adverse effects will be triggered that we will see in detail later. By presenting a high affinity to these receptors, olanzapine is able to significantly improve both the positive and negative symptoms of schizophrenia.
Finally, it should be mentioned that there is also a formulation of this drug so that it has a prolonged action.
Pharmacokinetics: what happens to olanzapine in the body?
Pharmacokinetics include the absorption, distribution, metabolism and elimination processes that the drug undergoes once administered. In this regard, olanzapine is administered orally and is rapidly absorbed.
Once absorbed, it reaches peak concentrations in plasma at 6 hours. It is important to note that the presence of food does not affect absorption, which is not the case with all medications.
The bioavailability of this drug is not very high, understanding bioavailability as the maximum concentration of the drug in the blood available at the time of exerting the action.
The reason for this is that it undergoes strong first-pass liver metabolism. In this way, only 40% of the administered dose reaches the systemic circulation.
Metabolism, which is a set of chemical reactions that the drug undergoes in the body in order to become more soluble and thus facilitate its elimination, takes place in the liver.
Once metabolized, the resulting substances, known as metabolites, may or may not trigger an effect in the body. In this case, the metabolites resulting from the chemical reactions that olanzapine undergoes in the body do not have pharmacological activity.
After being metabolized, both the metabolites and the resulting drug are eliminated approximately 30% in the urine and approximately 55% in the faeces.
Adverse reactions of olanzapine
The most common adverse reactions of this drug are:
- Weight gain.
- Drowsiness.
- Increased prolactin levels.
- Elevation of cholesterol, glucose and triglyceride levels.
- Dizziness
- Orthostatic hypotension.
- Constipation.
- Akathisia and dyskinesia.
Conclution
Olanzapine is a widely used drug for treating schizophrenia. Due to its powerful effects on the body, it is a drug subject to medical prescription. Therefore, you should not take it if it has not been indicated by a specialist. Always follow the instructions of your doctor or pharmacist and consult all the doubts you have with them.
