Mirtazapine is a tetracyclic antidepressant that is approved by the U.S. Food and Drug Administration (FDA) to help treat major depressive disorder (MDD).
The medication has sleep-promoting side effects, and may be prescribed off-label for insomnia.
If you have been prescribed mirtazapine, you might want to ask your healthcare provider about its sleep benefits,
In this article, I’ll explore what mirtazapine does, its potential side effects, interactions, and warnings.
I’ll also cover how you should know when to see a medical provider for sleep problems.
What is Mirtazapine?
Mirtazapine (Remeron) is an antidepressant that is prescribed for major depressive disorder.
It works to balance chemical messengers, known as neurotransmitters, that may contribute to symptoms of depression or low mood.
It also supports better nerve cell communication in the central nervous system.
Mirtazapine is a less commonly prescribed antidepressant, but that does not mean that it is not effective.
What Does It Treat?
Mirtazapine is mainly used for and is FDA-approved for the treatment of depression.
Mirtazapine helps to improve sleep, nausea, and appetite.
Healthcare providers may also prescribe mirtazapine off-label for the following:
- Panic disorder
- Post-traumatic stress disorder (PTSD), usually in combination with SSRIs
- Social anxiety disorder
When compared to other types of antidepressants, mirtazapine was found to be as effective as amitriptyline while causing fewer side effects.
When compared to selective serotonin reuptake inhibitors (SSRIs) like sertraline (Zoloft), citalopram (Celexa), paroxetine (Paxil), and fluoxetine (Prozac), mirtazapine was found equally effective, but with benefits seen faster than the SSRIs, as early as 1-2 weeks after starting treatment.
Patients taking mirtazapine were 74% more likely to achieve remission of depression-related symptoms than those who took SSRIs.
Mirtazapine For Sleep
Mirtazapine is not strictly a sleep medication, but some healthcare providers prescribe it to help address sleep-related problems and for the treatment of insomnia.
Like antihistamines, which are also used off-label to treat sleep disorders, mirtazapine can interfere with the histamine H1 receptor.
If this receptor is too active, it can prevent sleep. When it is blocked, it can induce some sedative-type effects.
A small study from 2002 found that mirtazapine was able to improve sleep duration when compared with a placebo.
It decreased the number of awakenings and increased the quality of sleep.
Other studies that have looked at how mirtazapine can affect sleep found that it can:
- Increase deep sleep (slow-wave sleep)
- Support falling asleep faster
- Reduce night-time awakenings and promote sleep continuity
- Increase melatonin levels
Because insomnia symptoms or other sleep-related problems may also be common in people who have depression, mirtazapine may be an effective medication to address both conditions.
While it does have some sleep benefits and can increase overall sleep quality, mirtazapine may decrease rapid eye movement (REM sleep).
Potential Side Effects
Not everyone may experience all of the side effects of mirtazapine, and they are generally mild.
Common side effects can include:
- Weight gain
- Increased appetite
- Dry mouth
- Drowsy feelings
- Lightheadedness or dizziness
- Feelings of mania
In some cases, serious side effects can occur.
If any of the following happen while taking mirtazapine, contact your medical provider immediately:
Immediate medical attention is necessary if someone taking mirtazapine faints, experiences a rapid heartbeat, has a seizure, or has changes to their vision.
Mirtazapine is available as an oral tablet or a tablet that dissolves in the mouth. Dosages for both formulations are the same.
Tablets are available in a dose of 7.5 mg, 15 mg, 30 mg, and 45 mg.
The starting dose is commonly 15 mg per day, taken once daily before bed.
A healthcare provider may increase the dosage up to 45 mg per day. The dosage may be gradually increased after taking mirtazapine for 1-2 weeks.
Mirtazapine has several possible drug interactions. These may affect how well the medication works.
Interactions can also lead to dangerous and preventable side effects.
Mirtazapine should not be taken with any of the following:
- Monoamine oxidase inhibitors (MAOIs)
- Linezolid (Zyvox)
- Intravenous methylene blue
- Other medications that increase the risk of serotonin syndrome, such as lithium or triptans
- Heart rhythm medications like amiodarone
- Phenytoin (Dilantin)
- Carbamazepine (Tegretol)
This is not a complete list of interactions.
Tell your medical provider and pharmacist about everything that you take, including over-the-counter (OTC) medications, herbs, and any dietary supplements.
Like other antidepressants, mirtazapine may increase the risk for thoughts of suicide, particularly in young adults.
If mirtazapine is taken with other medications or substances that affect serotonin levels, serious side effects can occur.
Mirtazapine may increase the risk of a heart problem known as QT prolongation.
People who are at higher risk of this complication are older adults, those who have a history of heart problems, and anyone who has low levels of potassium or magnesium.
Mirtazapine can cause drowsiness during the day.
You should not drive or operate heavy machinery until you know how the medication affects you.
Stopping mirtazapine suddenly can lead to complications.
If you need to stop taking mirtazapine, your healthcare provider will slowly taper your dosage to help avoid side effects or complications.
People who are pregnant should only take mirtazapine if their healthcare provider determines that it is the only possible option.
It can increase the risk of side effects in the infant, especially if it is used in the third trimester.
When to See a Doctor
If you have sleep problems and occasional OTC remedies are not working, see your healthcare provider.
They can recommend an appropriate treatment option.
They will ask about your symptoms, medical conditions, and other factors that you think may contribute to sleep problems.
If you already take mirtazapine, speak to a healthcare provider to understand:
- Your dosage
- Questions about side effects
- How mirtazapine may affect other aspects of your health
- How to use mirtazapine for sleep
- How to safely discontinue mirtazapine
If you’re having a mental health emergency, call 911 or go to the nearest emergency room. You can also get free 24/7 support from a suicide and crisis expert by calling or texting 988. If you’d prefer to chat online, you can chat with a suicide and crisis expert by visiting the Lifeline Chat.
How K Health Can Help
Think you might need a prescription for mirtazapine?
K Health has clinicians standing by 24/7 to evaluate your symptoms and determine if mirtazapine is right for you.
Get started with our free assessment, which will tell you in minutes if treatment could be a good fit. If yes, we’ll connect you right to a clinician who can prescribe medication and have it shipped right to your door.
Frequently Asked Questions
K Health has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references.
A Review of Therapeutic Uses of Mirtazapine in Psychiatric and Medical Conditions. (2013).
Histamine H₁ receptor occupancy by the new-generation antidepressants fluvoxamine and mirtazapine: a positron emission tomography study in healthy volunteers. (2013).
The effects of mirtazapine on sleep: a placebo controlled, double-blind study in young healthy volunteers. (2002).
Changes of sleep architecture, spectral composition of sleep EEG, the nocturnal secretion of cortisol, ACTH, GH, prolactin, melatonin, ghrelin, and leptin, and the DEX-CRH test in depressed patients during treatment with mirtazapine. (2006).
Remeron (mirtazapine tablets). (2009).