Antidepressant Basics: Remeron
Generic Name: Mirtazapine
Brand Names: • Remeron • Avanza • Axit • Mirtaz • Zispin
Class: Antidepressant, Tetracyclic
Updated: August 2014
What Is It?
REMERON (mirtazapine) is an antidepressant drug of the tetracyclic type. Manufactured by N.V. Organon, a subsidiary of Merck & Co., Inc.
What Does It Treat?
REMERON (mirtazapine) Tablets are indicated for the treatment of:
• major depressive disorder.
Off-label uses include the treatment for:
• post-traumatic stress disorder (PTSD)
The efficacy of REMERON Tablets as a treatment for major depressive disorder was established in 4 placebo-controlled, 6-week trials in adult outpatients meeting DSM-III criteria for major depressive disorder.
Some people have thoughts about suicide when first taking an antidepressant. Your doctor will need to check your progress at regular visits while you are using Remeron. Your family or other caregivers should also be alert to changes in your mood or symptoms.
This medication guide does not take the place of talking to your healthcare provider about your medical condition or treatment. Talk with your healthcare provider if there is something you do not understand or want to learn more about.
Do not start or stop any medicine while taking Remeron without talking to your healthcare provider first.
Who Should Not Take Remeron?
Do not take Remeron if you: 1) are allergic to Remeron or any of the ingredients in Remeron. See the end of this section for a complete list of ingredients in Remeron; 2) take a monoamine oxidase inhibitor (MAOI) or have taken an MAOI in the past 14 days. Ask your healthcare provider or pharmacist if you are not sure if you take an MAOI, including the antibiotic linezolid. Do not take an MAOI within 2 weeks of stopping Remeron unless directed to do so by your physician. Do not start Remeron if you stopped taking an MAOI in the last 2 weeks unless directed to do so by your physician. MAOIs include Parnate (Tranylcypromine), Nardil (Phenelzine), Emsam (Selegiline transdermal), and Marplan (Isocarboxazid).
Safety and effectiveness in the pediatric population have not been established. Do not give Remeron to anyone younger than 18 years old without the advice of a doctor.
Before Starting Remeron
Tell your healthcare provider about: 1) any medical conditions you have, including seizure, cardiac, liver, kidney, or blood disease; 2) current pregnancy or plans to become pregnant; 3) current breastfeeding or plans to breastfeed; 4) any and all medications and supplements you are taking; 5) any thoughts or feelings of suicide. Report any new or worsening symptoms to your doctor, such as: mood or behavior changes, anxiety, panic attacks, trouble sleeping, or if you feel impulsive, irritable, agitated, hostile, aggressive, restless, hyperactive (mentally or physically), more depressed, or have thoughts about suicide or hurting yourself.
Patients should be told that the concomitant use of Remeron and alcohol is not advised. Patients should avoid diazepam and all other depressants while taking Remeron. Patients should inform their physician if they are taking, or plan to take, any prescription or over-the-counter drugs, as there is a potential for interactions. Patients should notify their physician if they become pregnant or intend to become pregnant during therapy. Patients should notify their physician if they are breast feeding an infant. While patients may notice improvement with Remeron therapy, they should be advised to continue therapy as directed.
Ingredients of REMERON:
Active ingredient: mirtazapine. Inactive ingredients: 15 mg tablets: Starch (corn), hydroxypropyl cellulose, magnesium stearate, colloidal silicon dioxide, lactose, hypromellose, polyethylene glycol 8000, titanium dioxide, ferric oxide (yellow). 30 mg tablets: Starch (corn), hydroxypropyl cellulose, magnesium stearate, colloidal silicon dioxide, lactose, hypromellose, polyethylene glycol 8000, titanium dioxide, ferric oxide (yellow), ferric oxide (red). 45 mg tablets: Starch (corn), hydroxypropyl cellulose, magnesium stearate, colloidal silicon dioxide, lactose, hypromellose, polyethylene glycol 8000, titanium dioxide.
Indications and Usage
REMERON (mirtazapine) Tablets are indicated for the treatment of major depressive disorder. Off-label uses include the treatment for post-traumatic stress disorder (PTSD) and insomnia. The efficacy of REMERON (mirtazapine) Tablets as a treatment for major depressive disorder was established in 4 placebo-controlled, 6-week trials in adult outpatients meeting DSM-III criteria for major depressive disorder.
The physician who elects to use Remeron for extended periods should periodically re-evaluate the long-term usefulness of the drug for the individual patient.
REMERON (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 REMERON Tablets or within 14 days of stopping treatment with REMERON is contraindicated because of an increased risk of serotonin syndrome. The use of REMERON within 14 days of stopping an MAOI intended to treat psychiatric disorders is also contraindicated.
Starting REMERON 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
Common Side Effects
Endocrine metabolic: Increased appetite (17% ), Serum triglycerides raised (increases to 500 mg/dL or more: 6%), Weight gain (body weight increase of 7% or greater: adults 7.5%; pediatrics 49% )
Gastrointestinal: Constipation (13% ), Xerostomia (25% )
Hepatic: ALT/SGPT level raised (2% )
Neurologic: Asthenia (8% ), Dizziness (7% ), Somnolence (54% )
Psychiatric: Disturbance in thinking (3% )
Serious Side Effects
Hematologic: Agranulocytosis, Neutropenia
Hepatic: Cirrhosis of liver (less than 0.1% )
Neurologic: Grand mal seizure (less than 0.1% ), Status epilepticus
Psychiatric: Depression, exacerbation, Suicidal thoughts, Suicide
Other: Neuroleptic malignant syndrome, Serotonin syndrome (less than 0.1% )
Get emergency medical help if you have any of these signs of an allergic reaction: skin rash or hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Suicidality and Antidepressant Drugs
Antidepressants increased the risk compared to placebo of suicidal thinking and behavior (suicidality) in children, adolescents, and young adults in short-term studies of major depressive disorder (MDD) and other psychiatric disorders. Anyone considering the use of REMERON® (mirtazapine) Tablets or any other antidepressant in a child, adolescent, or young adult must balance this risk with the clinical need. 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. Depression and certain other psychiatric disorders are themselves associated with increases in the risk of suicide. Patients of all ages who are started on antidepressant therapy should be monitored appropriately and observed closely for clinical worsening, suicidality, or unusual changes in behavior. Families and caregivers should be advised of the need for close observation and communication with the prescriber. REMERON is not approved for use in pediatric patients.
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 18–24) with major depressive disorder (MDD) and other psychiatric disorders.
All patients being treated with antidepressants for any indication should be monitored appropriately and observed closely for clinical worsening, suicidality, and unusual changes in behavior, especially during the initial few months of a course of drug therapy, or at times of dose changes, either increases or decreases. Families and caregivers of patients being treated with antidepressants for major depressive disorder or other indications, both psychiatric and nonpsychiatric, should be alerted about the need to monitor patients for the emergence of agitation, irritability, unusual changes in behavior, and the other symptoms described above, as well as the emergence of suicidality, and to report such symptoms immediately to health care providers. Such monitoring should include daily observation by families and caregivers.
In premarketing clinical trials, 2 (1 with Sjögren’s Syndrome) out of 2796 patients treated with REMERON (mirtazapine) Tablets developed agranulocytosis [absolute neutrophil count (ANC) <500/mm3 with associated signs and symptoms, e.g., fever, infection, etc.] and a third patient developed severe neutropenia (ANC <500/mm3 without any associated symptoms). For these 3 patients, onset of severe neutropenia was detected on days 61, 9, and 14 of treatment, respectively. All 3 patients recovered after REMERON was stopped. These 3 cases yield a crude incidence of severe neutropenia (with or without associated infection) of approximately 1.1 per thousand patients exposed, with a very wide 95% confidence interval, i.e., 2.2 cases per 10,000 to 3.1 cases per 1000. If a patient develops a sore throat, fever, stomatitis, or other signs of infection, along with a low WBC count, treatment with REMERON should be discontinued and the patient should be closely monitored.
Screening Patients for Bipolar Disorder
A major depressive episode may be the initial presentation of bipolar disorder. It is generally believed (though not established in controlled trials) that treating such an episode with an antidepressant alone may increase the likelihood of precipitation of a mixed/manic episode in patients at risk for bipolar disorder. Whether any of the symptoms described above represent such a conversion is unknown. However, prior to initiating treatment with an antidepressant, patients with depressive symptoms should be adequately screened to determine if they are at risk for bipolar disorder; such screening should include a detailed psychiatric history, including a family history of suicide, bipolar disorder, and depression. It should be noted that REMERON (mirtazapine) Tablets are not approved for use in treating bipolar depression.
The development of a potentially life-threatening serotonin syndrome has been reported with SNRIs and SSRIs, including REMERON, alone but particularly with concomitant use of other serotonergic drugs (including triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, tryptophan, buspirone, and St. John’s wort), and with drugs that impair metabolism of serotonin (in particular, MAOIs, both those intended to treat psychiatric disorders and also others, such as linezolid and intravenous methylene blue). Serotonin syndrome symptoms may include mental status changes (e.g., agitation, hallucinations, delirium, and coma), autonomic instability (e.g., tachycardia, labile blood pressure, dizziness, diaphoresis, flushing, hyperthermia), neuromuscular symptoms (e.g., tremor, rigidity, myoclonus, hyperreflexia, incoordination), seizures, and/or gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea). Patients should be monitored for the emergence of serotonin syndrome. The concomitant use of REMERON with MAOIs intended to treat psychiatric disorders is contraindicated. REMERON should also not be started in a patient who is being treated with MAOIs such as linezolid or intravenous methylene blue. All reports with methylene blue that provided information on the route of administration involved intravenous administration in the dose range of 1 mg/kg to 8 mg/kg. No reports involved the administration of methylene blue by other routes (such as oral tablets or local tissue injection) or at lower doses. There may be circumstances when it is necessary to initiate treatment with an MAOI such as linezolid or intravenous methylene blue in a patient taking REMERON. REMERON should be discontinued before initiating treatment with the MAOI. If concomitant use of REMERON with other serotonergic drugs, including triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, buspirone, tryptophan, and St. John’s wort, is clinically warranted, be aware of a potential increased risk for serotonin syndrome, particularly during treatment initiation and dose increases. Treatment with REMERON and any concomitant serotonergic agents should be discontinued immediately if the above events occur and supportive symptomatic treatment should be initiated.
There is very limited experience with REMERON Tablets overdose. In premarketing clinical studies, there were 8 reports of REMERON overdose alone or in combination with other pharmacological agents. The only drug overdose death reported while taking REMERON was in combination with amitriptyline and chlorprothixene in a non-US clinical study. Based on plasma levels, the REMERON 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 REMERON alone. See the official REMERON medication guide.
Call 911 or the Poison Help line at 1-800-222-1222 for all suspected overdose cases.
Pregnancy Category C
Reproduction studies in pregnant rats and rabbits at doses up to 100 mg/kg and 40 mg/kg, respectively [20 and 17 times the maximum recommended human dose (MRHD) on an mg/m2 basis, respectively], have revealed no evidence of teratogenic effects. However, in rats, there was an increase in postimplantation losses in dams treated with mirtazapine. There was an increase in pup deaths during the first 3 days of lactation and a decrease in pup birth weights. The cause of these deaths is not known. The effects occurred at doses that were 20 times the MRHD, but not at 3 times the MRHD, on an mg/m2 basis. There are no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Because some REMERON may be excreted into breast milk, caution should be exercised when REMERON Tablets are administered to nursing women.
Safety and effectiveness in the pediatric population have not been established. Two placebo-controlled trials in 258 pediatric patients with MDD have been conducted with REMERON (mirtazapine) Tablets, and the data were not sufficient to support a claim for use in pediatric patients. Anyone considering the use of REMERON in a child or adolescent must balance the potential risks with the clinical need. In an 8-week-long pediatric clinical trial of doses between 15 to 45 mg/day, 49% of REMERON-treated patients had a weight gain of at least 7%, compared to 5.7% of placebo-treated patients. The mean increase in weight was 4 kg (2 kg SD) for REMERON-treated patients versus 1 kg (2 kg SD) for placebo-treated patients.
Approximately 190 elderly individuals (≥65 years of age) participated in clinical studies with REMERON (mirtazapine) Tablets. This drug is known to be substantially excreted by the kidney (75%), and the risk of decreased clearance of this drug is greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection. Sedating drugs may cause confusion and over-sedation in the elderly. No unusual adverse age-related phenomena were identified in this group. Pharmacokinetic studies revealed a decreased clearance in the elderly. Caution is indicated in administering REMERON to elderly patients
REMERON® (mirtazapine) Tablets 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 C17H19N3. Its molecular weight is 265.36. Mirtazapine is a white to creamy white crystalline powder which is slightly soluble in water. REMERON is supplied for oral administration as scored film-coated tablets containing 15 or 30 mg of mirtazapine, and unscored film-coated tablets containing 45 mg of mirtazapine. Each tablet also contains corn starch, hydroxypropyl cellulose, magnesium stearate, colloidal silicon dioxide, lactose, and other inactive ingredients.
The mechanism of action of REMERON (mirtazapine) Tablets, as with other drugs effective in the treatment of major depressive disorder, is unknown.
Evidence gathered in preclinical studies suggests that mirtazapine enhances central noradrenergic and serotonergic activity. These studies have shown that mirtazapine acts as an antagonist at central presynaptic α2–adrenergic inhibitory autoreceptors and heteroreceptors, an action that is postulated to result in an increase in central noradrenergic and serotonergic activity.
Mirtazapine is a potent antagonist of 5-HT2 and 5-HT3 receptors. Mirtazapine has no significant affinity for the 5-HT1A and 5-HT1B receptors.
Mirtazapine is a potent antagonist of histamine (H1) receptors, a property that may explain its prominent sedative effects.
Mirtazapine is a moderate peripheral α1–adrenergic antagonist, a property that may explain the occasional orthostatic hypotension reported in association with its use.
Mirtazapine is a moderate antagonist at muscarinic receptors, a property that may explain the relatively low incidence of anticholinergic side effects associated with its use.
REMERON (mirtazapine) Tablets are rapidly and completely absorbed following oral administration and have a half-life of about 20 to 40 hours. Peak plasma concentrations are reached within about 2 hours following an oral dose. The presence of food in the stomach has a minimal effect on both the rate and extent of absorption and does not require a dosage adjustment. Mirtazapine is extensively metabolized after oral administration. Major pathways of biotransformation are demethylation and hydroxylation followed by glucuronide conjugation. In vitro data from human liver microsomes indicate that cytochrome 2D6 and 1A2 are involved in the formation of the 8-hydroxy metabolite of mirtazapine, whereas cytochrome 3A is considered to be responsible for the formation of the N-desmethyl and N-oxide metabolite. Mirtazapine has an absolute bioavailability of about 50%. It is eliminated predominantly via urine (75%) with 15% in feces. Several unconjugated metabolites possess pharmacological activity but are present in the plasma at very low levels. The (–) enantiomer has an elimination half-life that is approximately twice as long as the (+) enantiomer and therefore achieves plasma levels that are about 3 times as high as that of the (+) enantiomer. Plasma levels are linearly related to dose over a dose range of 15 to 80 mg. The mean elimination half-life of mirtazapine after oral administration ranges from approximately 20 to 40 hours across age and gender subgroups, with females of all ages exhibiting significantly longer elimination half-lives than males (mean half-life of 37 hours for females vs. 26 hours for males). Steady state plasma levels of mirtazapine are attained within 5 days, with about 50% accumulation (accumulation ratio = 1.5). Mirtazapine is approximately 85% bound to plasma proteins over a concentration range of 0.01 to 10 mcg/mL.
Following oral administration of REMERON (mirtazapine) Tablets 20 mg/day for 7 days to subjects of varying ages (range, 25–74), oral clearance of mirtazapine was reduced in the elderly compared to the younger subjects. The differences were most striking in males, with a 40% lower clearance in elderly males compared to younger males, while the clearance in elderly females was only 10% lower compared to younger females. Caution is indicated in administering REMERON to elderly patients.
Safety and effectiveness of mirtazapine in the pediatric population have not been established (see PRECAUTIONS).
The mean elimination half-life of mirtazapine after oral administration ranges from approximately 20 to 40 hours across age and gender subgroups, with females of all ages exhibiting significantly longer elimination half-lives than males (mean half-life of 37 hours for females vs. 26 hours for males) (see Pharmacokinetics).
There have been no clinical studies to evaluate the effect of race on the pharmacokinetics of REMERON.
The disposition of mirtazapine was studied in patients with varying degrees of renal function. Elimination of mirtazapine is correlated with creatinine clearance. Total body clearance of mirtazapine was reduced approximately 30% in patients with moderate (Clcr=11–39 mL/min/1.73 m2) and approximately 50% in patients with severe (Clcr=
Following a single 15-mg oral dose of REMERON, the oral clearance of mirtazapine was decreased by approximately 30% in hepatically impaired patients compared to subjects with normal hepatic function. Caution is indicated in administering REMERON to patients with compromised hepatic function
Dosage and Administration
Dosage Forms and Strengths
REMERON (mirtazapine) Tablets are supplied as:
• 15 mg Tablets — oval, scored, yellow, coated, with “Organon” debossed on 1 side and “T3Z” on the other side. Bottles of 30, NDC 0052-0105-30
• 30 mg Tablets — oval, scored, red-brown, coated, with “Organon” debossed on 1 side and “T5Z” on the other side. Bottles of 30, NDC 0052-0107-30
• 45 mg Tablets — oval, white, coated, with “Organon” debossed on 1 side and “T7Z” on the other side. Bottles of 30, NDC 0052-0109-30
The recommended starting dose for REMERON (mirtazapine) Tablets is 15 mg/day, administered in a single dose, preferably in the evening prior to sleep. In the controlled clinical trials establishing the efficacy of REMERON in the treatment of major depressive disorder, the effective dose range was generally 15 to 45 mg/day. While the relationship between dose and satisfactory response in the treatment of major depressive disorder for REMERON has not been adequately explored, patients not responding to the initial 15-mg dose may benefit from dose increases up to a maximum of 45 mg/day. REMERON has an elimination half-life of approximately 20 to 40 hours; therefore, dose changes should not be made at intervals of less than 1 to 2 weeks in order to allow sufficient time for evaluation of the therapeutic response to a given dose.
Elderly and Patients with Renal or Hepatic Impairment
The clearance of mirtazapine is reduced in elderly patients and in patients with moderate to severe renal or hepatic impairment. Consequently, the prescriber should be aware that plasma mirtazapine levels may be increased in these patient groups, compared to levels observed in younger adults without renal or hepatic impairment.
It is generally agreed that acute episodes of depression require several months or longer of sustained pharmacological therapy beyond response to the acute episode. Systematic evaluation of REMERON (mirtazapine) Tablets has demonstrated that its efficacy in major depressive disorder is maintained for periods of up to 40 weeks following 8 to 12 weeks of initial treatment at a dose of 15 to 45 mg/day. Based on these limited data, it is unknown whether or not the dose of REMERON needed for maintenance treatment is identical to the dose needed to achieve an initial response. Patients should be periodically reassessed to determine the need for maintenance treatment and the appropriate dose for such treatment.