X
More than 60,000 patients use Brite
4.6 stars
Your health finally understandable with Brite
Enter email and you're done. No subscription, no credit card.
Search, tap and you're done. Over 3,400 medicines.
Check, remind, get an overview.
Sarah K., 34
I finally understand my therapy. The app reminds me, answers my questions — and I don't feel alone with it anymore.
Mirtazapine is an antidepressant with an unusual profile and is particularly suitable for depression with sleep disturbances and loss of appetite. About one in five adults develops depression over the course of their life, many of them with disturbed sleep and weight loss (a broadly Western figure). Unlike SSRIs, mirtazapine makes you drowsy quickly in the evening and causes barely any sexual side effects — the price for this is a frequently noticeable weight gain.
See more detail.gif)
Take mirtazapine in the evening. Antidepressant effect after 2–6 weeks, sleep effect often immediate. Never stop abruptly. With fever/sore throat, check the blood count (agranulocytosis). Last updated: May 2026.
Mirtazapine is an antidepressant with quite its own profile — it works sleep-promotingly and appetite-raisingly and has barely any sexual side effects. Below are the most important key facts for a quick orientation; the individual points are explained in detail in the following chapters.
| Property | Details |
|---|---|
| Active substance | Mirtazapine — an antidepressant from the group of the NaSSAs (noradrenergic and specific serotonergic antidepressants) |
| Trade names | Remergil, mirtazapine generics; also as an orodispersible tablet |
| ATC code | N06AX11 — other antidepressants |
| Mechanism of action | Blockade of alpha-2, 5-HT2, 5-HT3, and histamine receptors — raises indirectly the noradrenaline and serotonin release; the histamine blockade explains sedation and appetite raising |
| Main indication | Depression — especially with accompanying sleep disorders and appetite/weight loss |
| Usual dose | 15–45 mg once daily, in the evening; maximum dose 45 mg/day |
| Onset of effect | Sleep promotion often in the first night; antidepressant effect after 2–6 weeks |
| Half-life | 20–40 hours — enables a once-daily intake, a milder stopping |
| Dosage form | Tablet, orodispersible tablet |
| Particularity | Paradoxical dose effect: low doses often work MORE sedatingly than higher ones |
| Sexual side effects | Barely any — a big advantage over SSRIs/SNRIs |
| Dependence | None — but a slow tapering off necessary |
| Prescription status | Yes |
Mirtazapine is an antidepressant with quite its own effect profile, which distinguishes it clearly from the more frequently prescribed SSRIs and SNRIs. It belongs to the group of the noradrenergic and specific serotonergic antidepressants (NaSSA). It is known above all under the trade name Remergil. Its characteristic properties: it works sleep-promotingly and appetite-raisingly — which makes it particularly suitable for certain patients.
Precisely this profile makes mirtazapine the preferred choice with depression that goes along with pronounced sleep disorders and appetite or weight loss — symptoms that are common with depression. While SSRIs tend to work activatingly and can dampen the appetite, mirtazapine often brings about the opposite: better sleep and more appetite.
These properties are an advantage or disadvantage depending on the situation: anyone who sleeps poorly and has lost weight benefits — anyone who tends to weight gain anyway sees the appetite-raising effect critically. A further important plus point: mirtazapine causes — unlike SSRIs/SNRIs — barely any sexual side effects. We explain these special properties in separate chapters.
Mirtazapine works differently than most antidepressants. Instead of inhibiting the reuptake of messenger substances (like SSRIs/SNRIs), it blocks certain receptors — and thereby raises, on an indirect path, the release of noradrenaline and serotonin.
| Receptor blockade | Effect |
|---|---|
| Alpha-2 receptors | Works like "releasing a brake" — raises the release of noradrenaline and serotonin (the main antidepressant mechanism) |
| 5-HT2 and 5-HT3 serotonin receptors | Steers the serotonin effect in a targeted way — explains the absence of sexual side effects, nausea, and restlessness |
| Histamine H1 receptors | A strong blockade — explains the sleep-promoting and appetite-raising effect |
The strong histamine blockade is the key to understanding mirtazapine: it makes one tired (sedating) and raises the appetite — exactly the effects that antihistamines (e.g. older allergy remedies) also have. That is not a coincidental effect, but central to the effect profile.
Mirtazapine is well absorbed, the half-life is relatively long at about 20–40 hours — that enables the once-daily intake (in the evening) and leads to a milder stopping behaviour than with short-acting substances such as venlafaxine. The breakdown takes place in the liver via various CYP enzymes. There is an orodispersible tablet that dissolves on the tongue — practical with swallowing problems.
A surprising and clinically important particularity of mirtazapine: Low doses often work MORE sleep-inducingly than higher doses. That sounds nonsensical at first, but has a pharmacological explanation.
At a low dose (e.g. 7.5–15 mg), the strongly sedating histamine blockade predominates. At a higher dose (30–45 mg), the noradrenergic, slightly activating effect comes to bear more strongly and partly balances out the sedation. The result: a higher dose can feel less "slept-in" the next day than a low one.
The main indication. Mirtazapine is an effective antidepressant with moderate to severe depression — particularly suitable when sleep disorders, inner restlessness, or appetite/weight loss are in the foreground. It is also used when SSRIs/SNRIs have not worked sufficiently or their side effects (sexual disorders, nausea, restlessness) were problematic.
With depression-related sleep disorders, mirtazapine is often a first choice — it treats the depression and at the same time improves sleep, without an additional sleeping pill being necessary.
Mirtazapine is sometimes combined with an SSRI/SNRI (so-called "California rocket fuel") — the different mechanisms can complement each other, above all with hard-to-treat depression. This combination belongs in specialist hands.
Because of the sleep-promoting and appetite-raising effect, mirtazapine is occasionally used off-label — for example with stubborn sleep disorders or for raising appetite in certain situations. Such uses take place after medical consideration.
As with all antidepressants, the antidepressant effect needs time — it builds up over 2 to 6 weeks, with the full effect after about 6 weeks. A particularity of mirtazapine: some effects set in much earlier.
The fast effect on sleep is a practical advantage: while one waits for the mood improvement, one already benefits from the better sleep — which eases the adherence to therapy and relieves the exhaustion. With an absent antidepressant effect after 6 weeks, the therapy is adjusted.
The sleep-promoting effect is one of the hallmarks of mirtazapine and is based on the strong histamine blockade. This effect is often immediately noticeable and makes mirtazapine particularly valuable with depression with sleep disorders.
Important: mirtazapine is an antidepressant, not a pure sleeping pill. If it is used primarily against sleep disorders without depression, that is an off-label use after medical consideration. The advantage over classic sleeping pills is the absent addiction potential. More under sleep disorders.
Perhaps the most-discussed topic with mirtazapine — and a common reason for concern. Mirtazapine raises the appetite and leads in many patients to a weight gain, likewise through the histamine blockade. Depending on the situation, that is desired or undesired.
With depression with loss of appetite and weight loss — a common and burdensome symptom — the appetite-raising effect is therapeutically very welcome. It helps to regain the lost weight and to support the physical recovery.
Anyone who tends to overweight anyway or already has a raised weight sees the weight gain critically. The gain can amount to several kilograms and is one of the most common causes for premature stopping.
An important plus point of mirtazapine over SSRIs and SNRIs: it causes barely any sexual dysfunction. While loss of libido, erectile and orgasmic disorders are very common under SSRIs/SNRIs, mirtazapine is clearly more tolerable here.
The reason lies in the mechanism of action: mirtazapine blocks in a targeted way the serotonin receptors (5-HT2) that are responsible for the sexual side effects. Therefore mirtazapine is often the choice when a patient suffers from sexual side effects of an SSRI/SNRI — either as a switch or as a supplementary administration (mirtazapine can even partly balance out the sexual side effects of other antidepressants).
This advantage is clinically significant, because sexual side effects are a common reason for therapy discontinuations. Anyone who is sensitive here can have a more tolerable option with mirtazapine. This topic is treated in more detail on the page about sertraline.
