Mirtazapine
A sedating antidepressant that blocks α2 receptors, used for depression; it often increases appetite and weight.
Drug card
- Class
- NaSSA
- How it works
- Blocking α2 autoreceptors, so more norepinephrine and serotonin are released
- Used for
- Depression
- Known for
- Drowsiness
- Increased appetite and weight gain
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does mirtazapine work?
Mirtazapine, a tetracyclic compound, blocks central α2 autoreceptors and heteroreceptors, raising noradrenergic and serotonergic activity, and blocks 5-HT2 and 5-HT3 receptors. Its H1 blockade explains its marked sleepiness, and peripheral α1 blockade its postural dizziness. Its exact antidepressant mechanism is unclear.
Uses
What is mirtazapine used for?
- Depression
Side effects
Side effects of mirtazapine
- DrowsinessKnown for
- Increased appetite and weight gainKnown for
- Dizziness
- Dry mouth
- Raised cholesterol and triglycerides
- Raised liver enzymes
- Agranulocytosis (very low white cell count)Serious
- Serotonin syndromeSerious
- Suicidal thoughts in children and young adultsSerious
- Low sodium (hyponatremia)Serious
- QT prolongation and torsades de pointes, rarelySerious
- Severe skin reactions, such as Stevens-Johnson syndromeSerious
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- Stop it and check a blood count if fever, sore throat, mouth ulcers or other signs of infection appear.
- Never combine with an MAOI; leave 14 days between them.
- Use with care in liver or kidney disease, seizure disorders and in people with QT risk factors.
Good to know: Unlike SSRIs, it works by blocking α2 receptors rather than the serotonin transporter, and it is strongly sedating and raises appetite.
Remember it
A way to remember it
Mirtazapine brings sleep and snacks.
Strong H1 blockade makes it sedating, and increased appetite with weight gain is among its most common effects.
Written for biofideX
Its class
Noradrenergic and specific serotonergic antidepressants
NaSSAs block presynaptic α2-adrenergic autoreceptors and heteroreceptors, which normally hold back transmitter release, so central norepinephrine and serotonin activity rises; whether this fully explains the antidepressant effect is unclear. They also block 5-HT2 and 5-HT3 receptors and, strongly, H1 receptors, which accounts for their marked sedation.
Easily mixed up with tricyclic antidepressants and selective serotonin reuptake inhibitors.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Depression, anxiety and sleep
Mirtazapine is one of 15 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
Start Practicing