Mirtazapine

REMERON

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Pronunciation: mir-TAZ-a-peen (REM-e-ron)

Mirtazapine ballicule: receptor binding, kinetics and half-life diagram — Mechanism of action: Mirtazapine ballicule

Mirtazapine REMERON mascot mnemonic cartoon — Visual mnemonic: Mirtazapine mascot
**“(Remember) Mr Taz zapping”**
NaSSA stands for noradrenergic and specific serotonergic antidepressant
“I only block” → receptor blocker, not reuptake inhibitor
The gun is a reference to α2 agonist guanfacine → opposite effect

What it isAlpha-2 antagonist with potent H1 and serotonin-receptor blockade; depression, often with insomnia or poor appetite.

Why this oneIts combination of sleep, appetite and anti-nausea effects is uniquely useful in underweight or medically frail patients.

What limits itWeight gain and daytime sedation commonly end the trial; paradoxically, lower exposure can be more sedating.

Mirtazapine molecular structure (skeletal formula) — Molecular structure: Mirtazapine

FDA-approved for

depression (1996)

Off-label

insomnia
appetite stimulation
nausea

FDA label

Read the full label on DailyMed ↗

BOXED WARNING Suicidal thoughts and behaviors: increased risk in pediatric and young adult patients; not approved in pediatric patients.

FDA dosing	Population	Start	Target	Max
Major depressive disorder	Adult	15 mg QHS		45 mg QD

Titration Do not increase at intervals shorter than 1–2 weeks.

Renal Decrease dose in moderate–severe renal impairment.

Hepatic Decrease dose in hepatic impairment.

Instructions

Administer once daily, preferably in the evening before sleep.
Taper gradually when discontinuing rather than stopping abruptly.
Allow ≥14 days between an MAOI and mirtazapine in either direction.

Available strengths

tab 7.5, 15, 30, 45 mg
ODT 15, 30, 45 mg

Contraindications

MAOIs (concurrently or within 14 days) due to risk of serotonin syndrome

Cautions

Agranulocytosis/severe neutropenia
Serotonin syndrome (including when used alone)
Angle-closure glaucoma
QT prolongation/Torsades
DRESS and severe skin reactions
Increased appetite and weight gain
Somnolence
Activation of mania/hypomania
Seizures
Elevated cholesterol/triglycerides
Hyponatremia
Transaminase elevations

Adverse reactions

Somnolence
Increased appetite
Weight gain
Dizziness
Dry mouth
Constipation

Pregnancy Prolonged experience has not reliably identified a drug-associated risk of major birth defects or miscarriage.

Lactation Present in milk at low levels (RID 0.6–2.8%); no adverse effects reported in most breastfed infants.

Cost

Mirtazapine (REMERON)

What pharmacies pay · NADAC 9/30/26

Strength		#/mo	generic $/mo	CostPlus
7.5 mg	tab	30 qd	$10.46	offered
15 mg	tab	30 qd	$1.89	offered
30 mg	tab	30 qd	$2.66	offered
45 mg	tab	30 qd	$3.33	offered

⚠ BOXED WARNING

Suicidal thoughts and behaviors in patients under 25

Classes and tags

Clinical profile

Therapeutic safety burden2 / 4

Overdose danger1 / 4

Weight-gain liability2 / 4

Sedation liability3 / 4

QT / Torsades1 / 4

Direct muscarinic antagonism0 / 4

Embryofetal risk1 / 4

Legacy pregnancy categoryC

Defining liabilityMarked sedation and clinically meaningful weight gain

Serotonicity

This drug is routinely called serotonergic. By Gillman’s human-effect criteria it does not raise serotonin in the synapse.

Label contraindicationMAOIs (concurrently or within 14 days) due to risk of serotonin syndrome. The label governs prescribing; Gillman’s point concerns serotonin toxicity only.

Gillman’s four human testsA measurable SERT affinity that fails all four is not clinical serotonicity.

Retarded orgasm
Efficacy in OCD and cataplexy
Clonus and hyperreflexia in single-drug overdose
Serotonin toxicity when combined with an MAOI

Background: what serotonicity is · what is and is not an SRI · what counts as a relevant MAOI.

Active metabolites

(Desmethyl-) mirtazapine

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Memory aids: interaction avatars

CYP1A2 substrate

CYP3A4 substrate

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