Each film-coated tablet contains 30mg of mirtazapine.
Pharmacotherapeutic group: Antidepressants. ATC code: N06AX11.
Pharmacology: Pharmacodynamics: Mirtazapine is a presynaptic alpha2-antagonist, which increases noradrenergic and serotonergic neurotransmission in the central nervous system. The serotonergic effect is a result of a specific action on the 5-HT1-receptors, since mirtazapine blocks both the 5-HT2- and the 5-HT3-receptors. Both enantiomers of mirtazapine are active agents.
The S(+) enantiomer blocks alpha2- and 5-HT2-receptors, whereas the R(-) enantiomer blocks 5-HT3-receptors. The H1-antagonistic effect is considered to the cause of the sedative effect of mirtazapine. The anticholinergic effect of mirtazapine is minimal and within therapeutic doses there are seldom clinically significant cardiovascular adverse events.
Mirtazapine is an antidepressant, which can be used to treat the episodes of major depression. The presence of symptoms such as anhedonia, psychomotor inhibition, sleep disturbances (early wakening) and weight loss, increase the chance of a positive response. Other symptoms are: loss of interest, suicidal thoughts and changes in mood (better in the evening than in the morning). Mirtazapine begins to exert its effect in general after 1 to 2 weeks of treatment.
Paediatric population: Two randomised, double-blind, placebo-controlled trials in children aged between 7 and 18 years with major depressive disorder (n=259) using a flexible dose for the first 4 weeks (15-45mg mirtazapine) followed by a fixed dose (15, 30 or 45 mg mirtazapine) for another 4 weeks failed to demonstrate significant differences between mirtazapine and placebo on the primary and all secondary endpoints. Significant weight gain (≥7%) was observed in 48.8% of the Remeron treated subjects compared to 5.7% in the placebo arm. Urticaria (11.8% vs 6.8%) and hypertriglyceridaemia (2.9% vs 0%) were also commonly observed.
Pharmacokinetics: Absorption: After oral administration of mirtazapine tablets, the active substance mirtazapine is rapidly and well absorbed (bioavailability about 50%), reaching peak plasma levels after about 2 hours. Food intake has no influence on the pharmacokinetics of mirtazapine.
Distribution: About 85% of mirtazapine is bound to plasma proteins. Steady state concentrations are reached after 3-4 days, after which there is no further accumulation. Mirtazapine displays linear pharmacokinetics within the recommended dose range.
Metabolism and elimination: The mean half-life of elimination is 20-40 hours; longer half-lives, up to 65 hours, have occasionally been recorded but in young men the half-lives have been shorter.
Mirtazapine is metabolized effectively and eliminated in urine and faeces over a few days. Biotransformation mainly occurs through demethylation and oxidation and subsequent conjugation. In vitro studies of human liver microsomes show that cytochrome P450 enzymes CYP2D6 and CYP1A2 are involved in the formation of the mirtazapine 8-hydroxy metabolite, whereas the CYP3A4 enzyme is assumed to be responsible for the formation of the N-demethyl and N-oxide metabolites. The demethyl metabolite is pharmacologically active, and its pharmacokinetic profile is similar to that of non-metabolized drug.
Special patient populations: The clearance of mirtazapine may be decreased in patients with renal or hepatic insufficiency.
Toxicology: Preclinical safety data: Preclinical data reveal no special hazard for humans based on conventional studies of safety pharmacology, repeated dose toxicity, carcinogenicity, genotoxicity or reproductive toxicity.
Mirtazapine induced no effects of clinical relevance in chronic safety studies in rats or dogs and reproductive toxicity studies in rats or rabbits. In reproductive toxicity studies in rats and rabbits at high dose levels, 20 and 17 times the maximum human dose at mg/m2 basis, respectively, no teratogenic effects were observed. There were, however, increase in post-implantation loss, decrease in the pup birth weights, and reduction in pup survival during the first three days of lactation. Mirtazapine was not genotoxic in a series of tests for gene mutation and chromosomal and DNA damage. Thyroid gland tumours found in a rat carcinogenicity study and hepatocellular neoplasms found in a mouse carcinogenicity study are considered to be species-specific, non-genotoxic responses associated with long-term treatment with high doses of hepatic enzyme inducers.
Major depressive episode.
The tablets should be swallowed whole without chewing, with a sufficient amount of fluid.
The tablets can be taken with or without food.
Adults: The initial dose is 15 or 30mg, taken preferably in the evening. The maintenance dose is usually between 15mg and 45mg per day.
Elderly patients: As in adults. Changes, especially increments of dosage must be made cautiously and under close supervision.
Children and adolescents under 18 years of age: Mirtazapine should not be used in children and adolescents under the age of 18 years as efficacy was not demonstrated in two short-term clinical trials (see Pharmacology: Pharmacodynamics under Actions) and because of safety concerns (see Precautions, Adverse Reactions and Pharmacology: Pharmacodynamics under Actions).
Renal or hepatic insufficiency: The elimination of mirtazapine may be slower in patients with renal or hepatic insufficiency. This must be considered when mirtazapine is prescribed for these patients or the clinical responses are interpreted.
Mirtazapine tablets can be taken once daily, since the elimination half-life is 20 to 40 hours. The medicine should be taken preferably as a single dose immediately before bedtime. The daily dose can also be divided into two doses taken in the morning and at bedtime. The larger dose should be taken in the evening.
The antidepressive effect of mirtazapine usually becomes evident after 1 to 2 weeks use. Treatment with an adequate dose should result in a positive response within 2 to 4 weeks. With an insufficient response, the dose can be increased up to the maximum dose. After having obtained an optimal clinical effect and the patient is free of symptoms, the treatment should be continued for 4 to 6 months, until a gradual discontinuation can be considered. If no clinical response is observed within 2 to 4 weeks of treatment with the maximum dose, the treatment should be gradually discontinued. Gradually tapering down the dosage is necessary to avoid withdrawal symptoms.
Present experience concerning overdose with mirtazapine alone indicates that symptoms are usually mild. Depression of the central nervous system with disorientation and prolonged sedation have been reported, together with tachycardia and mild hyper- or hypotension. However, there is a possibility of more serious outcomes (including fatalities) at dosages much higher than therapeutic dose, especially with mixed overdosages. Overdosage is treated with activated charcoal, support of vital functions and symptomatic treatment. Gastric lavage may be considered, if necessary.
Hypersensitivity to mirtazapine or any of the excipients.
Suicide/suicidal thoughts or clinical worsening: Depression is associated with an increased risk of suicidal thoughts, self-harm and suicide (suicide-related events). This risk persists until significant remission occurs. As improvement may not occur during the first few weeks or more of treatment, patients should be closely monitored until such improvement occurs. It is general clinical experience that the risk of suicide may increase in the early stages of recovery.
Patients with a history of suicide-related events, or those exhibiting a significant degree of suicidal ideation prior to commencement of treatment are known to be at greater risk of suicidal thoughts or suicide attempts, and should receive careful monitoring during treatment. A meta-analysis of placebo-controlled clinical trials of antidepressant drugs in adult patients with psychiatric disorders showed an increased risk of suicidal behaviour with antidepressants compared to placebo in patients less than 25 years old.
Close supervision of patients and in particular those at high risk should accompany drug therapy with antidepressants especially in early treatment and following dose changes. Patients (and caregivers of patients) should be alerted about the need to monitor for any clinical worsening, suicidal behaviour or thoughts and unusual changes in behaviour and to seek medical advice immediately if these symptoms present. With regard to the chance of suicide, in particular at the beginning of treatment, only a limited number of Mirtazapine Tablets should be given to the patient.
Bone marrow depression: Bone marrow depression, which is usually manifested by granulocytopenia or agranulocytosis, has been reported in the users of mirtazapine. This effect is usually seen after 4 to 6 weeks of treatment, but it usually disappears after discontinuation of treatment. Reversible agranulocytosis has also been reported as a rare occurrence in clinical trials with mirtazapine. The attendant doctor should be alert for fever, throat pain, stomatitis and other signs and symptoms suggestive of infection. If these manifestations occur, the treatment should be discontinued and a complete blood count should be taken.
The medicinal product is to be used with caution, and careful monitoring to be applied in patients with: Epilepsy or organic brain syndrome; although clinical experience indicates that epileptic seizures are rare during mirtazapine treatment and should be introduced cautiously in patients who have a history of seizures.
Hepatic impairment: Following a single 15 mg oral dose of mirtazapine, the clearance of mirtazapine was approximately 35% decreased in mild to moderate hepatically impaired patients, compared to subjects with normal hepatic function. The average plasma concentration of mirtazapine was about 55% increased.
Renal impairment: Following a single 15 mg oral dose of mirtazapine, in patients with moderate (creatinine clearance <40 ml/min) and severe (creatinine clearance ≤ 10 ml/min) renal impairment the clearance of mirtazapine was about 30% and 50% decreased respectively, compared to normal subjects. The average plasma concentration of mirtazapine was about 55% and 115% increased respectively. No significant differences were found in patients with mild renal impairment (creatinine clearance <80 ml/min) as compared to the control group.
Heart disease, such as conduction disturbances, angina pectoris or recent myocardial infarction, which requires conventional precautions and caution during concurrent administration of other medicinal products.
Hypotension.
Like with other antidepressants, caution should be exercised when the medicinal product is administered to patients with: micturition disturbances, such as prostatic hyperplasia (although mirtazapine is only slightly anticholinergic).
Acute narrow angle glaucoma and elevated intraocular pressure (during mirtazapine treatment, the risk of these problems is very low because of the low anticholinergic effect of mirtazapine).
Diabetes mellitus: antidepressants may alter glycaemic control. Insulin and/or hypoglycaemic dosage may need to be adjusted and dose monitoring is recommended.
Jaundice: The treatment should be discontinued in the presence of jaundice.
Like in the case of other antidepressants, the following should be considered: An exacerbation of psychotic symptoms may occur when schizophrenia or other psychoses are treated with antidepressants; paranoid thoughts can also be intensified.
When the depressive phase of a bipolar disorder is being treated, a switch to a manic phase may occur. Patients with a history of mania/hypomania should be closely monitored. Mirtazapine should be discontinued in any patient entering a manic phase.
Akathisia/psychomotor restlessness: The use of antidepressants have been associated with the development of akathisia, characterized by a subjectively unpleasant or distressing restlessness and need to move often accompanied by an inability to sit or stand still. This is most likely to occur within the first few weeks of treatment. In patients who develop these symptoms, increasing the dose may be detrimental.
Although antidepressants do not cause dependency, abrupt cessation of long-term treatment may cause dizziness, anxiety, agitation, nausea, headache and malaise. As advised in Dosage & Administration, it is recommended to discontinue treatment with mirtazapine gradually.
Elderly patients are often more sensitive, especially to the undesirable effects of antidepressants. In clinical studies of mirtazapine, the reported incidence of undesirable effects has not been any higher in elderly patients than in other age groups. However, experience is still limited.
Hyponatraemia: Hyponatraemia, probably due to inappropriate antidiuretic hormone secretion (SIADH), has been reported very rarely with the use of mirtazapine. Caution should be exercised in patients at risk, such as elderly patients or patients concomitantly treated with medications known to cause hyponatraemia.
Serotonin syndrome: Interaction with serotonergic active substances: serotonin syndrome may occur when selective serotonin reuptake inhibitors (SSRIs) are used concomitantly with other serotonergic active substances (see Interactions). Symptoms of serotonin syndrome may be hyperthermia, rigidity, myoclonus, autonomic instability with possible rapid fluctuations of vital signs, mental status changes that include confusion, irritability and extreme agitation progressing to delirium and coma. From post marketing experience it appears that serotonin syndrome occurs very rarely in patients treated with Mirtazapine Tablets alone (see Adverse Reactions).
Lactose: Mirtazapine tablets contain lactose. Patients with rare hereditary problems of galactose intolerance, Lapp lactase deficiency or glucose-galactose malabsorption should not take this medicine.
Effects on ability to drive and use machines: Mirtazapine may moderately impair concentration and alertness, especially in the beginning of treatment. This should be considered before engaging in tasks requiring special alertness and concentration, such as driving and operating dangerous machines.
Use in children: Use in children and adolescents under 18 years of age: Mirtazapine 30mg Tablets should not be used in the treatment of children and adolescents under the age of 18 years. Suicide-related behaviours (suicide attempt and suicidal thoughts), and hostility (predominantly aggression, oppositional behaviour and anger) were more frequently observed in clinical trials among children and adolescents treated with antidepressants compared to those treated with placebo. If, based on clinical need, a decision to treat is nevertheless taken; the patient should be carefully monitored for the appearance of suicidal symptoms. In addition, long-term safety data in children and adolescents concerning growth, maturation and cognitive and behavioural development are lacking.
Epidemiological data have suggested that the use of SSRIs in pregnancy, particularly in late pregnancy, may increase the risk of persistent pulmonary hypertension in the newborn (PPHN). Although no studies have investigated the association of PPHN to mirtazapine treatment, this potential risk cannot be ruled out taking into account the related mechanism of action (increase in serotonin concentrations).
There are no adequate data from the use of mirtazapine in pregnant women. Studies in animals have not shown any teratogenic effect or reproductive toxicity of clinical relevance (see Pharmacology: Toxicology: Preclinical safety data under Actions). The potential risk for humans is unknown. Mirtazapine should not be used during pregnancy unless clearly indicated following a careful clinical risk/benefit consideration.
Although animal experiments show that mirtazapine is excreted only in very small amounts in the milk, the use of mirtazapine in breast-feeding mothers is not recommended. No human data is available.
Depressed patients display a number of symptoms that are associated with the illness itself. It is therefore sometimes difficult to ascertain which symptoms are a result of the illness itself and which are a result of mirtazapine treatment.
The most commonly reported adverse reactions, occurring in more than 5% of patients treated with mirtazapine in randomised placebo-controlled trials (see as follows) are somnolence, sedation, dry mouth, weight increased, increase in appetite, dizziness and fatigue.
All randomised placebo-controlled trials in patients (including indications other than major depressive disorder), have been evaluated for adverse reactions of mirtazapine. The meta-analysis considered 20 trials, with a planned duration of treatment up to 12 weeks, with 1501 patients (134 person years) receiving doses of mirtazapine up to 60mg and 850 patients (79 person years) receiving placebo. Extension phases of these trials have been excluded to maintain comparability to placebo treatment.
The table as follows shows the categorized incidence of the adverse reactions, which occurred in the clinical trials statistically significantly more frequently during treatment with mirtazapine than with placebo, added with adverse reactions from spontaneous reporting. The frequencies of the adverse reactions from spontaneous reporting are based on the reporting rate for these events in the clinical trials. The frequency of adverse reactions from spontaneous reporting for which no cases in the randomised placebo-controlled patient trials were observed with mirtazapine has been classified as 'not known'. (See table.)
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In laboratory evaluations in clinical trials transient increases in transaminases and gamma-glutamyltransferase have been observed (however associated adverse events have not been reported statistically significantly more frequently with Mirtazapine than with placebo).
Paediatric population: The following adverse events were observed commonly in clinical trials in children: Weight gain, Urticaria, Hypertriglyceridaemia.
See also Pharmacology: Pharmacodynamics under Actions.
Pharmacodynamic interactions: Mirtazapine should not be administered concomitantly with MAO inhibitors or within 14 days after discontinuation of MAO inhibitor therapy. In the opposite way about two weeks should pass before patients treated with mirtazapine should be treated with MAO inhibitors (see Contraindications).
In addition, as with SSRIs, co-administration with other serotonergic active substances (L-tryptophan, triptans, tramadol, linezolid, SSRIs, venlafaxine, lithium and St. John's Wort- Hypericum perforatum preparations) may lead to an incidence of serotonin associated effects (serotonin syndrome: see Precautions). Caution should be advised and a closer clinical monitoring is required when these active substances are combined with mirtazapine.
Mirtazapine may increase the sedating properties of benzodiazepines and other sedatives (notably most antipsychotics, antihistamines H1 antagonists, opioids). Caution should be exercised when these medicinal products are prescribed together with mirtazapine.
Mirtazapine may increase the CNS depressant effect of alcohol. Patients should therefore be advised to avoid alcoholic beverages while taking mirtazapine.
Mirtazapine dosed at 30mg once daily caused a small but statistically significant increase in the international normalised ratio (INR) in subjects treated with warfarin. As at a higher dose of mirtazapine a more pronounced effect cannot be excluded, it is advisable to monitor the INR in case of concomitant treatment of warfarin with mirtazapine.
Pharmacokinetic interactions: Carbamazepine and phenytoin, CYP3A4 inducers, increased mirtazapine clearance about twofold, resulting in a decrease in average plasma mirtazapine concentration of 60% and 45%, respectively. When carbamazepine or any other inducer of hepatic metabolism (such as rifampicin) is added to mirtazapine therapy, the mirtazapine dose may have to be increased. If treatment with such medicinal products is discontinued, it may be necessary to reduce the mirtazapine dose.
Co-administration of the potent CYP3A4 inhibitor ketoconazole increased the peak plasma levels and the AUC of mirtazapine by approximately 40% and 50% respectively.
When cimetidine (weak inhibitor of CYP1A2, CYP2D6 and CYP3A4) is administered with mirtazapine, the mean plasma concentration of mirtazapine may increase more than 50%. Caution should be exercised and the dose may have to be decreased when co-administering mirtazapine with potent CYP3A4 inhibitors, HIV protease inhibitors, azole antifungals, erythromycin, cimetidine or nefazodone.
Interaction studies did not indicate any relevant pharmacokinetic effects on concurrent treatment of mirtazapine with paroxetine, amitriptyline, risperidone or lithium.
N06AX11 - mirtazapine ; Belongs to the class of other antidepressants.
Merasal FC tab 30 mg
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