What Is Remeron (Mirtazapine) Used For?
Remeron is the brand name for mirtazapine, an antidepressant approved in the US for depression. It works differently from SSRIs and is known for sleepiness and a bigger appetite.
By withClaro Editorial · 2026-11-02 · 4 min read
Clinical section reviewed by Dr. Jason Tan, Consultant Psychiatrist, on October 27, 2026.
More about Remeron
Key takeaways
- Remeron is the brand name for mirtazapine, approved in the US for depression in adults.
- It is not an SSRI but a tetracyclic antidepressant: it blocks alpha-2 receptors and acts on norepinephrine and serotonin systems, and its histamine blocking explains the sleepiness.
- It starts at 15 mg at bedtime and can go up to 45 mg.
- Sleepiness, a bigger appetite and weight gain are its most common side effects.
Remeron is used for depression in adults. Its generic name is mirtazapine, and it was first approved in the US in 1996. Rather than blocking serotonin reuptake like SSRIs, it blocks several receptors in the brain, which is also why it is known for sleepiness and a bigger appetite. In 2024 mirtazapine was prescribed about 5.6 million times in the US, by ClinCalc estimates.
What is Remeron used for?
Its only FDA-approved use is major depressive disorder in adults, as tablets or the SolTab that dissolves on the tongue. It is not approved for sleep, anxiety or appetite.
Is Remeron an SSRI?
No. Mirtazapine has a tetracyclic structure and is usually grouped on its own rather than with SSRIs. SSRIs such as Zoloft and Lexapro block serotonin reuptake; mirtazapine doesn't, and instead blocks alpha-2 receptors and the serotonin receptors 5-HT2 and 5-HT3. For the other types, see the list of antidepressants.
How does Remeron work?
Medically reviewed by Dr. Jason Tan on October 27, 2026, this section only.
The label says how it treats depression is unclear, but its effect may come from blocking alpha-2 receptors in the brain, which acts on the norepinephrine and serotonin systems; it also blocks the serotonin receptors 5-HT2 and 5-HT3. It blocks histamine H1 receptors too, and the label says this may explain its strong sleepiness. The clinical view:
Antidepressants change how the brain uses chemical messengers, but how this lifts mood is not fully understood.
The chemical change starts within hours, yet the full effect on mood takes weeks. Current thinking points to early changes in how the brain processes emotion, then slower changes in receptors, in brain circuits that handle emotion, and in how the brain forms new connections. For mirtazapine, this means its main effects come from the receptors it blocks rather than from reuptake, and the label links its sleepiness to the histamine blocking.
What doses does Remeron come in?
Remeron tablets come in 15 mg and 30 mg, and the SolTab, which dissolves on the tongue, in 15 mg, 30 mg and 45 mg. The label starts at 15 mg in the evening, before sleep, and allows up to 45 mg. More in Remeron dosage.
What side effects does Remeron cause?
Sleepiness, in about half of people. The figures come from 6-week US trials with 453 people on Remeron and 361 on placebo:
| Side effect | Remeron | Placebo |
|---|
| Sleepiness | 54% | 18% |
| Dry mouth | 25% | 15% |
| Increased appetite | 17% | 2% |
| Weight gain | 12% | 2% |
| Dizziness | 7% | 3% |
The label asks you not to drive until you know how Remeron affects you, and to avoid alcohol. More in Remeron side effects.
Two warnings need a call rather than a wait. The label warns about a rare drop in white blood cells: a sore throat, fever, mouth sores or other signs of infection need a call to your prescriber. Like every US antidepressant, it carries an FDA boxed warning about suicidal thoughts in people 24 and younger. If you're having thoughts of harming yourself, contact emergency services or a crisis line straight away. In the US, call or text 988. In the UK, call Samaritans on 116 123. Elsewhere, find a crisis line near you.
Does the sleepiness on Remeron go away?
It may not. The label says it is unclear whether people get used to it, and in the trials 10.4% stopped Remeron because of sleepiness, against 2.2% on placebo. That is why it is taken at bedtime, and why it is worth telling your prescriber at the first follow-up how sleepy you are in the morning.
What should you tell your prescriber before starting Remeron?
Some conditions and medications change whether Remeron is a good fit, and the label lists them among its warnings, so name them at the first appointment. Before you start, tell your prescriber about:
- weight concerns, diabetes or high cholesterol
- kidney or liver problems
- other antidepressants and medicines that make you sleepy
- heart rhythm problems, seizures or a history of mania
- pregnancy, plans for pregnancy or breastfeeding
Write down your answers before the visit, and ask how sleepy you are likely to be in the first weeks, what to do about appetite, and when you will review how it is going.
Download on the App Store Remeron can change sleep and appetite before mood. The withClaro app lets you log mood, sleep, appetite and side effects each day, linked to your dose, and turns it into a report for your prescriber.
Related articles
Sources
- REMERON (mirtazapine) prescribing information, US Food and Drug Administration via DailyMed, revised November 2021
- ClinCalc DrugStats: The Top 300 Drugs of 2024
Claro articles are for self-monitoring and educational purposes only. They are not a medical device, therapist, or diagnostic tool, and do not replace care from your prescribing clinician. If you are in crisis, contact your care team, emergency services, the Samaritans (UK: 116 123), or the Crisis Text Line (US: text HOME to 741741).