Learn the common signs of mental illness in adults and adolescents.
Learn more about common mental health conditions that affect millions.
Find Your Local NAMI
Call the NAMI Helpline at
Or in a crisis, text "NAMI" to 741741
Generic name: mirtazapine (mir TAZ a peen)
All FDA black box warnings are at the end of this fact sheet. Please review before taking this medication.
Mirtazapine is an antidepressant medication that works in the brain. It is approved for the treatment of major depressive disorder (MDD).
Symptoms of depression include:
Do not stop taking mirtazapine, even when you feel better. With input from you, your health care provider will assess how long you will need to take the medicine.
Missing doses of mirtazapine may increase your risk for relapse in your symptoms.
Stopping mirtazapine abruptly may result in one or more of the following withdrawal symptoms: irritability, nausea, dizziness, vomiting, nightmares, headache, and/or paresthesias (prickling, tingling sensation on the skin).
Depression is also a part of bipolar illness. People with bipolar disorder who take antidepressants may be at risk for "switching" from depression into mania. Symptoms of mania include "high" or irritable mood, very high self-esteem, decreased need for sleep, pressure to keep talking, racing thoughts, being easily distracted, frequently involved in activities with a large risk for bad consequences (for example, excessive buying sprees).
Medical attention should be sought if serotonin syndrome is suspected. Please refer to serious side effects for signs/symptoms.
If you are planning on becoming pregnant, notify your health care provider to best manage your medications. People living with MDD who wish to become pregnant face important decisions. Untreated MDD has risks to the fetus, as well as the mother. It is important to discuss the risks and benefits of treatment with your doctor and caregivers.
Caution is advised with breastfeeding since mirtazapine does pass into breast milk.
Mirtazapine is usually taken one time per day at bedtime with or without food.
Typically patients begin at a low dose of medicine and the dose is increased slowly over several weeks.
The dose usually ranges from 15 mg to 45 mg. Only your health care provider can determine the correct dose for you.
Mirtazapine orally disintegrating tablets will dissolve in your mouth within seconds and can be swallowed with or without liquid.
Mirtazapine orally disintegrating tablets must remain in their original packaging. Open the package with clean dry hands before each dose. Do not try to put tablets in a pillbox if you take the orally disintegrating tablets.
Consider using a calendar, pillbox, alarm clock, or cell phone alert to help you remember to take your medication. You may also ask a family member or friend to remind you or check in with you to be sure you are taking your medication.
If you miss a dose of mirtazapine, take it as soon as you remember, unless it is closer to the time of your next dose. Discuss this with your health care provider. Do not double your next dose or take more than what is prescribed.
Avoid drinking alcohol or using illegal drugs while you are taking antidepressant medications. They may decrease the benefits (e.g., worsen your condition) and increase adverse effects (e.g., sedation) of the medication.
If an overdose occurs, call your doctor or 911. You may need urgent medical care. You may also contact the poison control center at 1-800-222-1222.
A specific treatment to reverse the effects of mirtazapine does not exist.
Common side effects
Rare/serious side effects
Angle closure glaucoma (symptoms of angle closure glaucoma may include eye pain, changes in vision, swelling or redness in or around eye)
Agranulocytosis (low white blood cell count) can increase the risk of infection. If you develop symptoms of infection, such as fever, chills, sore throat, swelling of the lining the mouth or other possible signs of infection, contact your prescriber.
Serotonin syndrome (symptoms may include shivering, diarrhea, confusion, severe muscle tightness, fever, seizures, and death), seizures.
To date, there are no known problems associated with long term use of mirtazapine. It is a safe and effective medication when used as directed.
Mirtazapine should not be taken with or within 2 weeks of taking monoamine oxidase inhibitors (MAOIs). These include phenelzine (Nardil®), tranylcypromine (Parnate®), isocarboxazid (Marplan®), rasagiline (Azilect®), and selegiline (Emsam®).
Although rare, there is an increased risk of serotonin syndrome when mirtazapine is used with other medications that increase serotonin, such as other antidepressants, migraine medications called “triptans” (e.g., Imitrex®), some pain medications (e.g., tramadol (Ultram®), and the antibiotic linezolid (Zyvox®).
Sleep, energy, or appetite may show some improvement within the first 1-2 weeks. Improvement in these physical symptoms can be an important early signal that the medication is working. Depressed mood and lack of interest in activities may need up to 6-8 weeks to fully improve.
Suicidal thoughts or actions in children and adults
Depression and certain other psychiatric disorders are themselves associated with increases in the risk of suicide. 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. This risk may persist until significant remission occurs.
In short-term studies, antidepressants increased the risk of suicidality in children, adolescents, and young adults when compared to placebo. Short-term studies did not show an increase in the risk of suicidality with antidepressants compared to placebo in adults beyond age 24. Adults age 65 and older taking antidepressants have a decreased risk of suicidality. Patients, their families, and caregivers should be alert to the emergence of anxiety, restlessness, irritability, aggressiveness and insomnia. If these symptoms emerge, they should be reported to the patient’s prescriber or health care professional. All patients being treated with antidepressants for any indication should watch for and notify their health care provider for worsening symptoms, suicidality and unusual changes in behavior, especially during the first few months of treatment.
©2020 The College of Psychiatric and Neurologic Pharmacists (CPNP) and the National Alliance on Mental Illness (NAMI). CPNP and NAMI make this document available under the Creative Commons Attribution-No Derivatives 4.0 International License. Last Updated: January 2016.
This information is being provided as a community outreach effort of the College of Psychiatric and Neurologic Pharmacists. This information is for educational and informational purposes only and is not medical advice. This information contains a summary of important points and is not an exhaustive review of information about the medication. Always seek the advice of a physician or other qualified medical professional with any questions you may have regarding medications or medical conditions. Never delay seeking professional medical advice or disregard medical professional advice as a result of any information provided herein. The College of Psychiatric and Neurologic Pharmacists disclaims any and all liability alleged as a result of the information provided herein.
Call the NAMI Helpline at
In a crisis,