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Quick facts
- How it is given
- oral
- Type
- human prescription drug
- RxNorm ID
- 311725
We do not publish dosing. How much of this medicine to take, how often, and for how long depends on your age, weight, kidney and liver function, other conditions and other medicines. That is a decision for the person who prescribes or dispenses it. Follow the directions on your own pack and ask your pharmacist if anything is unclear.
What it is used to treat
INDICATIONS AND USAGE Mirtazapine tablets are indicated for the treatment of major depressive disorder. The efficacy of mirtazapine in the treatment of major depressive disorder was established in 6-week controlled trials of outpatients whose diagnoses corresponded most closely to the Diagnostic and Statistical Manual of Mental Disorders-3rd edition (DSM-III) category of major depressive disorder (see CLINICAL PHARMACOLOGY ). A major depressive episode (DSM-IV) implies a prominent and relatively persistent (nearly every day for at least 2 weeks) depressed or dysphoric mood that usually interferes with daily functioning, and includes at least 5 of the following 9 symptoms: depressed mood, loss of interest in usual activities, significant change in weight and/or appetite, insomnia or hypersomnia, psychomotor agitation or retardation, increased fatigue, feelings of guilt or worthlessness, slowed thinking or impaired concentration, a suicide attempt, or suicidal ideation. The effectiveness of mirtazapine in hospitalized depressed patients has not been adequately studied. The efficacy of mirtazapine in maintaining a response in patients with major depressive disorder for up to 40 weeks following 8 to 12 weeks of initial open-label treatment was demonstrated in a placebo-controlled trial. Nevertheless, the physician who elects to use mirtazapine for extended periods should periodically re-evaluate the long-term usefulness of the drug for the individual patient (see CLINICAL PHARMACOLOGY ).
About this medicine
DESCRIPTION Mirtazapine tablets, USP are an orally administered drug. Mirtazapine has a tetracyclic chemical structure and belongs to the piperazino-azepine group of compounds. It is designated 1,2,3,4,10,14b-hexahydro-2-methylpyrazino[ 2,1-a] pyrido [ 2,3-c] benzazepine and has the empirical formula of C 17 H 19 N 3 . Its molecular weight is 265.36. The structural formula is the following and it is the racemic mixture: Mirtazapine USP is a white to creamy white crystalline powder which is slightly soluble in water. Mirtazapine tablets, USP are supplied for oral administration as scored film-coated tablets containing 15 or 30 mg of mirtazapine USP, and unscored film-coated tablets containing 7.5 or 45 mg of mirtazapine USP. Each tablet also contains corn starch, hydroxypropyl cellulose, magnesium stearate, colloidal silicon dioxide, lactose monohydrate, hypromellose, and titanium dioxide. In addition, the 15 mg contains iron oxide yellow and 30 mg contains iron oxide red, iron oxide black, and iron oxide yellow. Mirtazpine Structure
Who should not take it
CONTRAINDICATIONS Hypersensitivity Mirtazapine tablets are contraindicated in patients with a known hypersensitivity to mirtazapine or to any of the excipients. Monoamine Oxidase Inhibitors The use of monoamine oxidase inhibitors (MAOIs) intended to treat psychiatric disorders with mirtazapine tablets or within 14 days of stopping treatment with mirtazapine tablets are contraindicated because of an increased risk of serotonin syndrome. The use of mirtazapine tablets within 14 days of stopping an MAOI intended to treat psychiatric disorders is also contraindicated (see WARNINGS and DOSAGE AND ADMINISTRATION ). Starting mirtazapine tablets in a patient who is being treated with MAOIs such as linezolid or intravenous methylene blue is also contraindicated because of an increased risk of serotonin syndrome (see WARNINGS and DOSAGE AND ADMINISTRATION ).
Warnings
WARNINGS Clinical Worsening and Suicide Risk Patients with major depressive disorder (MDD), both adult and pediatric, may experience worsening of their depression and/or the emergence of suicidal ideation and behavior (suicidality) or unusual changes in behavior, whether or not they are taking antidepressant medications, and this risk may persist until significant remission occurs. Suicide is a known risk of depression and certain other psychiatric disorders, and these disorders themselves are the strongest predictors of suicide. There has been a long-standing concern, however, that antidepressants may have a role in inducing worsening of depression and the emergence of suicidality in certain patients during the early phases of treatment. Pooled analyses of short-term placebo-controlled trials of antidepressant drugs (SSRIs and others) showed that these drugs increase the risk of suicidal thinking and behavior (suicidality) in children, adolescents, and young adults (ages 18 to 24) with major depressive disorder (MDD) and other psychiatric disorders. Short-term studies did not show an increase in the risk of suicidality with antidepressants compared to placebo in adults beyond age 24; there was a reduction in risk with antidepressants compared to placebo in adults aged 65 and older. The pooled analyses of placebo-controlled trials in children and adolescents with MDD, obsessive compulsive disorder (OCD), or other psychiatric disorders included a total of 24 short-term trials of 9 antidepressant drugs in over 4400 patients. The pooled analyses of placebo-controlled trials in adults with MDD or other psychiatric disorders included a total of 295 short-term trials (median duration of 2 months) of 11 antidepressant drugs in over 77,000 patients. There was considerable variation in risk of suicidality among drugs, but a tendency toward an increase in the younger patients for almost all drugs studied. There were differences in absolute risk of suicidality across different indications, with the highest incidence in MDD. The risk differences (drug vs. placebo), however, were relatively stable within age strata and across indications. […]
Reported side effects
ADVERSE REACTIONS Associated with Discontinuation of Treatment Approximately 16 % of the 453 patients who received mirtazapine tablets in US 6-week controlled clinical trials discontinued treatment due to an adverse experience, compared to 7 % of the 361 placebo-treated patients in those studies. The most common events (≥ 1%) associated with discontinuation and considered to be drug related (i.e., those events associated with dropout at a rate at least twice that of placebo) included in Table 2. Table 2: Common Adverse Events Associated With Discontinuation of Treatment in 6-Week U.S. Mirtazapine Trials Adverse Event Percentage of Patients Discontinuing with Adverse Event Mirtazapine (n=453) Placebo (n=361) Somnolence 10.4% 2.2% Nausea 1.5% 0% Commonly Observed Adverse Events in U.S. Controlled Clinical Trials The most commonly observed adverse events associated with the use of mirtazapine tablets (incidence of 5% or greater) and not observed at an equivalent incidence among placebo-treated patients (mirtazapine incidence at least twice that for placebo) are listed in Table 3. Table 3: Common Treatment –Emergent Adverse Events Associated With the Use of Mirtazapine in 6-Week U.S. Trials Adverse Event Percentage of Patients Reporting Adverse Event Mirtazapine (n=453) Placebo (n=361) Somnolence 54% 18% Increased Appetite 17% 2% Weight Gain 12% 2% Dizziness 7% 3% Adverse Events Occurring at an Incidence of 1% or More Among Mirtazapine-Treated Patients Table 4 enumerates adverse events that occurred at an incidence of 1% or more, and were more frequent than in the placebo group, among mirtazapine tablets-treated patients who participated in short-term US placebo-controlled trials in which patients were dosed in a range of 5 to 60 mg/day. This table shows the percentage of patients in each group who had at least 1 episode of an event at some time during their treatment. Reported adverse events were classified using a standard COSTART-based dictionary terminology. […]
Interactions with other medicines
Drug Interactions As with other drugs, the potential for interaction by a variety of mechanisms (e.g., pharmacodynamic, pharmacokinetic inhibition or enhancement, etc.) is a possibility (see CLINICAL PHARMACOLOGY ). Monoamine Oxidase Inhibitors (See CONTRAINDICATIONS , WARNINGS , and DOSAGE AND ADMINISTRATION .) Serotonergic Drugs (See CONTRAINDICATIONS and WARNINGS .) Drugs Affecting Hepatic Metabolism The metabolism and pharmacokinetics of mirtazapine tablets may be affected by the induction or inhibition of drug-metabolizing enzymes. Drugs that are Metabolized by and/or Inhibit Cytochrome P450 Enzymes CYP Enzyme Inducers (these studies used both drugs at steady state) Phenytoin In healthy male patients (n=18), phenytoin (200 mg daily) increased mirtazapine (30 mg daily) clearance about 2-fold, resulting in a decrease in average plasma mirtazapine concentrations of 45%. Mirtazapine did not significantly affect the pharmacokinetics of phenytoin. Carbamazepine In healthy male patients (n=24), carbamazepine (400 mg b.i.d.) increased mirtazapine (15 mg b.i.d.) clearance about 2-fold, resulting in a decrease in average plasma mirtazapine concentrations of 60%. When phenytoin, carbamazepine, or another inducer of hepatic metabolism (such as rifampicin) is added to mirtazapine therapy, the mirtazapine dose may have to be increased. If treatment with such a medicinal product is discontinued, it may be necessary to reduce the mirtazapine dose. CYP Enzyme Inhibitors Cimetidine In healthy male patients (n=12), when cimetidine, a weak inhibitor of CYP1A2, CYP2D6, and CYP3A4, given at 800 mg b.i.d. at steady state was coadministered with mirtazapine (30 mg daily) at steady state, the Area Under the Curve (AUC) of mirtazapine increased more than 50%. Mirtazapine did not cause relevant changes in the pharmacokinetics of cimetidine. The mirtazapine dose may have to be decreased when concomitant treatment with cimetidine is started, or increased when cimetidine treatment is discontinued. Ketoconazole In healthy, male, Caucasian patients (n=24), coadministration of the potent CYP3A4 inhibitor ketoconazole (200 mg b.i.d. […]
If too much is taken
OVERDOSAGE Human Experience There is very limited experience with mirtazapine tablets overdose. In premarketing clinical studies, there were 8 reports of mirtazapine overdose alone or in combination with other pharmacological agents. The only drug overdose death reported while taking mirtazapine was in combination with amitriptyline and chlorprothixene in a non-US clinical study. Based on plasma levels, the mirtazapine dose taken was 30 to 45 mg, while plasma levels of amitriptyline and chlorprothixene were found to be at toxic levels. All other premarketing overdose cases resulted in full recovery. Signs and symptoms reported in association with overdose included disorientation, drowsiness, impaired memory, and tachycardia. There were no reports of ECG abnormalities, coma, or convulsions following overdose with mirtazapine tablets alone. However, based on postmarketing reports, there is a possibility of more serious outcomes (including fatalities) at dosages much higher than the therapeutic dose, especially with mixed overdoses. In these cases, QT prolongation and Torsades de Pointes have also been reported (see PRECAUTIONS , Drug Interactions and ADVERSE REACTIONS sections). Overdose Management Treatment should consist of those general measures employed in the management of overdose with any drug effective in the treatment of major depressive disorder. Ensure an adequate airway, oxygenation, and ventilation. Monitor cardiac rhythm and vital signs. General supportive and symptomatic measures are also recommended. Induction of emesis is not recommended. Gastric lavage with a large-bore orogastric tube with appropriate airway protection, if needed, may be indicated if performed soon after ingestion, or in symptomatic patients. Activated charcoal should be administered. There is no experience with the use of forced diuresis, dialysis, hemoperfusion, or exchange transfusion in the treatment of mirtazapine overdosage. No specific antidotes for mirtazapine are known. In managing overdosage, consider the possibility of multiple-drug involvement. […]
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This page is built from the openFDA record of the U.S. Food and Drug Administration's approved labelling for this product, effective 8 March 2019. Label text has been shortened and reformatted for readability; safety wording has not been altered in meaning. FDA labelling describes products approved in the United States — brand names, strengths, formulations and approved uses may differ in your country. Always read the leaflet that comes with your own pack. PocketsInfo is not affiliated with, and is not endorsed by, the FDA. Retrieved 2026-07-30.