Medication Guide
Mirtazapine (Remeron) Side Effects and Uses
A plain-language guide to Mirtazapine, an Atypical antidepressant (noradrenergic and specific serotonergic). Learn how it helps, what it treats, how to take it and which side effects to know about.
Quick answer. Mirtazapine (Remeron) is an Atypical antidepressant (noradrenergic and specific serotonergic). Common mirtazapine side effects include sleepiness or next-morning grogginess, bigger appetite, weight gain and dry mouth. The rare but serious ones, and when to get help, are listed under mirtazapine side effects below. Never stop or change your dose on your own.
How Mirtazapine Can Help You
Mirtazapine (Remeron) is an atypical antidepressant. It boosts norepinephrine and serotonin. It does this in a different way from SSRIs and SNRIs. Its first effects are often better sleep and appetite. These can start in the first few nights.
That is a real plus when depression has caused poor sleep, low appetite or weight loss. The fuller effect on mood then builds on that base.
Sleep often improves within days. Mood usually improves over two to six weeks. It causes little nausea. It also causes fewer sexual side effects than many antidepressants. It can be combined with another antidepressant when one is not enough. Your prescriber weighs its effects on sleep and appetite against your needs.
Uses for Mirtazapine
- Major depressive disorder
- Depression with poor sleep
- Depression with poor appetite or weight loss
- Insomnia (off-label)
- Generalized anxiety disorder (off-label)
- Post-traumatic stress disorder (off-label)
- Add-on to an SSRI or SNRI for hard-to-treat depression (off-label)
How to Take Mirtazapine
Your prescriber decides your dose and any changes. It makes you drowsy. So it is taken once a day in the evening, before sleep. You can take it with or without food. It comes as a regular tablet and a tablet that melts on the tongue.
Take it at about the same time each night. If you miss a dose and it is close to morning, skip it. A late dose can leave you groggy. Then go back to your usual time the next night. Do not stop mirtazapine suddenly. Stopping symptoms tend to be milder than with SSRIs. Still, a slow taper is the safe way.
Mirtazapine Side Effects
Common Side Effects
- Sleepiness or next-morning grogginess
- Bigger appetite
- Weight gain
- Dry mouth
- Constipation
- Dizziness
- Vivid dreams
- Higher cholesterol or triglycerides
Serious: Get Medical Help Promptly
- New or worse suicidal thoughts, mostly in people under 25 (boxed warning)
- A rare drop in infection-fighting white cells (agranulocytosis), with fever, sore throat or mouth sores
- Serotonin syndrome when combined with other serotonin drugs
- Mania, with a very high or irritable mood
- Severe skin reactions
- Low sodium (hyponatremia), mostly in older adults
How Mirtazapine Works
Most antidepressants block the reuptake of serotonin. Mirtazapine works another way. It blocks certain receptors that act as brakes. Those brakes normally hold back norepinephrine and serotonin. The result is more of both chemicals at work.
Mirtazapine also blocks histamine, the same target as many allergy pills. That is the main reason it causes sleepiness and a bigger appetite. It also spares many of the serotonin receptors linked to nausea and sexual side effects.
Before You Start Mirtazapine
Mirtazapine must never be taken with an MAOI antidepressant. Alcohol, benzodiazepines and other sedating drugs add to drowsiness. Ask before combining them. Do not drive until you know how it affects you. The tablet that melts on the tongue contains phenylalanine. This matters for people with PKU.
Tell your prescriber about liver or kidney disease, high cholesterol and seizures. Also share heart problems and any history of bipolar disorder. Share your weight goals too, since appetite often rises. If you are thinking about harming yourself, call or text 988, or call 911. Learn about sleep problems and depression care by telehealth.
Is Mirtazapine Right for You?
Only a full evaluation with a prescriber can tell you if Mirtazapine fits your symptoms, history and goals. Harpal Singh, PMHNP-BC offers psychiatric evaluations and ongoing medication management by telehealth anywhere in California.
SCHEDULE AN APPOINTMENT CALL (888) 457-8124
Related Medication Guides
Other guides in the same group, written the same simple way. Being in one group does not mean you can swap one medicine for another.
- Bupropion (Wellbutrin XL), Atypical antidepressant (norepinephrine-dopamine reuptake inhibitor)
- Citalopram (Celexa), SSRI antidepressant
- Desvenlafaxine (Pristiq), SNRI antidepressant
- Doxepin (Silenor), Tricyclic antidepressant (TCA)
- Duloxetine (Cymbalta), SNRI antidepressant
- Escitalopram (Lexapro), SSRI antidepressant
FAQ
Questions About Mirtazapine
Why is mirtazapine taken at night?
Mirtazapine blocks histamine, which makes it quite sedating. For people whose depression comes with poor sleep, that can be a help. Taking it at bedtime puts the sleepiness where it is useful, and morning grogginess often eases within a week or two.
Will mirtazapine make me gain weight?
A bigger appetite and weight gain are among its most common side effects. That can help if depression has cut your appetite, but it may be unwelcome otherwise. Talk about your weight goals with your prescriber before you start.
Is it true lower doses are more sedating?
You may hear this, but it is not true for everyone. How sleepy you feel depends on you, your dose and other medicines. If daytime sleepiness is a problem, tell your prescriber rather than changing the dose yourself.
Does mirtazapine cause sexual side effects?
Much less often than SSRIs and SNRIs. It largely spares the serotonin receptors linked to those effects. That makes it a reasonable option for people who could not tolerate other antidepressants for that reason.
When should I call my prescriber urgently?
Call right away if you get a fever, sore throat or mouth sores, which can be rare signs of low white cells. Also call for a very high mood or a severe rash. If you are thinking about harming yourself, call or text 988, or call 911.
How long does mirtazapine take to work?
Sleep and appetite often improve within days. Mood usually improves over two to six weeks. Keep taking it as prescribed during this time.
Can I drink alcohol while taking mirtazapine?
It is best to avoid alcohol. Alcohol adds to the sleepiness and slowed thinking mirtazapine can cause. It can also make depression worse.
Can mirtazapine be taken with another antidepressant?
Sometimes, yes. Prescribers sometimes add mirtazapine to an SSRI or SNRI when one medicine is not enough. Because both affect serotonin, your prescriber reviews the combination and the signs of serotonin syndrome to watch for.