Mirtazapine is a commonly used antidepressant with a well known ability to produce sedation and weight gain. Mirtazapine is usually used by prescribers to target the respective depressive symptoms of poor sleep, poor appetite, and weight loss.
 BRAND NAMES
- International: Remeron
- Australia: Avanza, Axit
- Finland: Mirtazon
- Ireland: Zispin
- Italy: Remeron
- Taiwan: Mirtazon
- UK: Zispin
- U.S.: Remeron PI
 MECHANISM OF ACTION
Mirtazapine is a noradrenergic and specific serotonergic antidepressant (NaSSA). It increases synaptic serotonin and noradrenaline release from nerve endings by antagonism of presynaptic α2-adrenergic receptors involved in feedback inhibition.
Serotonin neurotransmission, specifically at the 5-HT1A receptor is thought to be responsible for therapeutic effects of antidepressants
Mirtazapine also blocks postsynaptic 5-HT2a and 5-HT3 receptors, H1 histamine receptors and has a moderate peripheral α1-adrenergic and muscarinic antagonist
- Major depressive disorder (Symptoms can include depressed or dysphoric mood, loss of interest in daily activities, weight change, insomnia or hypersomnia, agitation or retardation, impaired concentration, and suicidal ideation)
- Obsessive-compulsive disorder
- Post-traumatic stress disorder
The recommended starting dose is 15 mg/day, titrate up to 15-45 mg/day with dose increases made no more frequently than every 1-2 weeks in order to allow sufficient time for evaluation of the therapeutic response to a given dose.
Take Mirtazapine as a once-a-day dose at bedtime
- patients with a known hypersensitivity to mirtazapine
- The concomitant use of Mirtazapine and a monoamine oxidase (MAO) inhibitor is contraindicated. Mirtazapine should not be used within 14 days of initiating or discontinuing therapy with a monoamine oxidase inhibitor (MAOI)
Patients should be monitored for signs of agranulocytosis or severe neutropenia such as sore throat, stomatitis or other signs of infection or a low white blood cell (WBC) count
- Monoamine Oxidase Inhibitors (rasagiline, selegiline): Concomitant use of mirtazapine with MAOIs is contraindicated. At least 14 days should elapse between discontinuation of an MAOI and initiation of therapy with mirtazapine. In addition, at least 14 days should be allowed after stopping Mirtazapine before starting an MAOI.
 PREGNANCY AND LACTATION
- Pregnancy Category C (US) (Mirtazapine should be used during pregnancy only if clearly needed).
- It is not known whether Mirtazapine is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Mirtazapine is administered to nursing women.
 SIDE EFFECTS
- Antihistamine effects include somnolence, increased appetite and weight gain
- Other side effects are orthostatic hypotension, dry mouth, constipation, increased cholesterol and triglyceride levels, increase in liver enzyme levels, neutropenia, and agranulocytosis (most serious side effect)
 RELATED LINKS
|Tricyclic antidepressants||Amitriptyline (Elavil, Laroxyl) • Clomipramine (Anafranil) • Doxepin (Sinequan) • Imipramine (Tofranil) • Nortriptyline (Aventyl, Pamelor) • Trimipramine (Surmontil)|
|Selective serotonin reuptake inhibitors (SSRIs)||Citalopram (Celexa, Seropram) • Escitalopram (Cipralex, Lexapro) • Fluoxetine (Prozac) • Fluvoxamine (Luvox, Maveral) • Paroxetine (Paxil, Seroxat) • Sertraline (Zoloft)|
|Serotonin–norepinephrine reuptake inhibitors (SNRIs)||Desvenlafaxine (Pristiq) • Duloxetine (Cymbalta, Xeristar) • Venlafaxine (Efexor, Effexor)|
|Serotonin antagonists and reuptake inhibitors (SARIs)||Trazodone (Desyrel, Oleptro)|
|Norepinephrine reuptake inhibitors (NRIs)||Maprotiline (Ludiomil) • Reboxetine (Edronax)|
|Norepinephrine-dopamine reuptake inhibitors (NDRIs)||Bupropion (Wellbutrin)|
|Noradrenergic and specific serotonergic antidepressants (NaSSAs)||Mianserin (Lantanon) • Mirtazapine (Remeron)|
|Norepinephrine-dopamine disinhibitors (NDDIs)||Agomelatine (Valdoxan, Thymanax)|
|Monoamine oxidase inhibitors Nonselective||Tranylcypromine (Parnate)|
|Monoamine oxidase inhibitors B-Selective||Selegiline (Transdermal) (Emsam)|
|Others||5-Hydroxytryptophan • S-Adenosyl methionine • Hypericum (St John's wort)|