Antidepressant tetracyclic structure. Enhances central adrenergic and serotonergic transmission. It blocks serotonin 5-HT2 and 5-HT3 receptors, in this regard, increased serotonergic transmission is realized only through serotonin 5-HT1 receptors. Both spatial enantiomers are involved in the manifestation of antidepressant activity: S (+) - the enantiomer blocks α2-adrenergic receptors and serotonin 5-HT2 receptors. Moderately blocks histamine H1 receptors, has a sedative effect. Little effect on α1-adrenergic receptors and cholinergic receptors; in therapeutic doses does not significantly affect the cardiovascular system. In clinical conditions, anxiolytic and hypnotic effects are also manifested, therefore, mirtazapine is most effective for anxious depressions of various origins. Due to the moderate sedative effect in the treatment process, suicidal thoughts are not actualized.Pharmacokinetics
Mirtazapine after oral administration is rapidly absorbed from the digestive tract. Bioavailability is 50%. Cmax in plasma is reached after 2 hours. Css in blood plasma is established after 3-4 days of constant intake. Plasma protein binding is 85%. It is actively metabolized in the liver by demethylation and oxidation, followed by conjugation. Dimethyl-mirtazapine is as pharmacologically active as the starting material. Mirtazapine is excreted by the kidneys and through the intestines. T1 / 2 is 20-40 hours. With renal and hepatic insufficiency, a decrease in the clearance of mirtazapine is possible.Contraindications
Renal and liver failure, pregnancy, lactation, hypersensitivity to mirtazapine.Pregnancy and lactation
Contraindicated in pregnancy and lactation.Side effects
From the side of the central nervous system and peripheral nervous system: drowsiness, lethargy, emotional lability, changes in mentality, agitation, anxiety, apathy, hallucinations, depersonalization, hostility, mania, epileptic seizures, dizziness, vertigo, hyperesthesia, convulsions, tremorzine, myoclonus, myoclone . Hematopoietic organs: inhibition of hematopoiesis - granulocytopenia, agranulocytosis, neutropenia, eosinophilia, aplastic anemia, thrombocytopenia. From the side of metabolism: a slight increase in appetite and weight gain; in isolated cases - edema. From the cardiovascular system: rarely - orthostatic hypotension. From the digestive system: nausea, vomiting, constipation, increased appetite, weight gain, dry mouth, thirst, abdominal pain; in isolated cases - an increase in the activity of liver transaminases. From the reproductive system: decreased potency, dysmenorrhea. Other: skin rashes, urticaria, flu-like syndrome, suffocation, edematous syndrome, myalgia, dysuria back pain.Interaction
With the simultaneous use of mirtazapine enhances the sedative effect of benzodiazepine derivatives. A case of the development of a hypertensive crisis with simultaneous use with clonidine is described. With simultaneous use with levodopa, a case of the development of severe psychosis is described; with sertraline - a case of hypomania. With simultaneous use with ethanol, it is possible to increase the inhibitory effect of ethanol and ethanol-containing preparations on the central nervous system.Dosage and administration
The method of application and the dosage regimen of a particular drug depends on its form of release and other factors. The optimal dosage regimen is determined by the doctor. The compliance of the dosage form of a particular preparation with the indications for use and the dosage regimen should be strictly observed. When administered, the effective dose for adults is 15-45 mg / day, mainly 1 time / day before bedtime. The dose is gradually increased to 30-45 mg / day. The antidepressant effect develops gradually, usually after 2-3 weeks from the start of treatment, however, administration should be continued for another 4-6 months. If within 6-8 weeks of treatment the therapeutic effect is not observed, treatment should be discontinued. The abolition of mirtazapine is carried out gradually.Special instructions
It is used with caution in patients with epilepsy and organic brain lesions, with impaired liver and / or kidney function, acute cardiovascular disease, with arterial hypotension, with urination impairment due to benign prostatic hyperplasia, with angle-closure glaucoma, and diabetes mellitus. In patients with schizophrenia, mirtazapine can cause increased delirium, hallucinations. In the treatment of the depressive phase of manic-depressive psychosis, this condition can go into the manic phase. Sudden discontinuation of mirtazapine after prolonged treatment may cause nausea, headache, and poor health. It should be borne in mind that when symptoms such as fever, sore throat, stomatitis appear during treatment, stop treatment and do a clinical blood test. If jaundice occurs, mirtazapine should be discontinued. It should not be used simultaneously with MAO inhibitors and within 2 weeks after their withdrawal. Perhaps the development of drug dependence, withdrawal syndrome. During treatment, patients should refrain from drinking alcohol. Mirtazapine is not used in children due to the lack of data on the effectiveness and safety of its use in pediatric practice. Influence on the ability to drive vehicles and control mechanisms Use with caution in patients whose activity is associated with the need for a high concentration of attention and speed of psychomotor reactions.