Mirtazapine (Remeron)

Raw research findings for this medication. Mostly single studies, not curated or confirmed robust.

About Mirtazapine

What it is

Mirtazapine is a tetracyclic antidepressant that blocks alpha-2 adrenergic receptors, increasing the release of noradrenaline and serotonin, and blocks some serotonin and histamine receptors, which makes it sedating and appetite-stimulating. It is used for depression, especially with poor sleep or poor appetite. It is sold as Remeron and Zispin, among other names.

How genes come into it

Mirtazapine is broken down by CYP2D6, CYP1A2 and CYP3A4. CYP2D6 poor metabolizers have somewhat higher levels of one of its mirror-image forms, rated at PharmGKB level 2A, but no guideline calls for a change. Studies have also looked at FKBP5, TPH2, CYP2B6 and others for response. There is no CPIC or DPWG guideline.

What research found

Every published finding on gene variants and Mirtazapine. Upload your DNA file to see which of these rows apply to you.

Rated evidence (10 rated variants)

PharmGKB weighs all studies of a variant and rates how strong the evidence is, from 1A (strongest) to 4.

CYP2D6 CYP2D6*1, CYP2D6*1xN, CYP2D6*3, CYP2D6*4, CYP2D6*5, CYP2D6*6: Level 2A · replicated. Metabolism/PK. 5.

TPH2 rs1487278: Level 3. Efficacy: Depression. 1.

TPH2 rs10879346: Level 3. Efficacy: Major Depressive Disorder. 1.

FKBP5 rs4713916: Level 3. Efficacy: Mood Disorder. 1.

Metabolism (1 finding)

Studies of how quickly the body processes this medication.

CYP2B6 CYP2B6*6: CYP2B6 *6/*6 is associated with increased metabolism of mirtazapine in people with Depression.

Response (8 findings)

Studies of how well it worked in people carrying a variant.

CYP2B6 CYP2B6*6: CYP2B6 *6/*6 is associated with increased response to mirtazapine in people with Depression.

CYP2D6 CYP2D6*1xN, CYP2D6*2xN: CYP2D6 *1xN + *2xN are associated with decreased response to citalopram, mianserin, mirtazapine, nortriptyline, paroxetine or venlafaxine in people with Mood Disorders.

FKBP5 rs4713916: Allele A is associated with increased response to citalopram, fluoxetine, mirtazapine, paroxetine, Selective serotonin reuptake inhibitors or venlafaxine in people with Mood Disorders as compared to allele G.

GAL rs948854: Allele C is associated with decreased response to antidepressants, benzodiazepine derivatives, mirtazapine or Selective serotonin reuptake inhibitors in women Depressive Disorder, Major as compared to allele T.

Study findings and evidence levels: PharmGKB (CC BY-SA 4.0). Guidelines: CPIC and DPWG, as bundled in PharmCAT. Most studies were done mainly in people of European ancestry.

Related Drugs

More drugs from the same category

Ludiomil (Tetracyclic Antidepressants)

Abilify (Antipsychotics)

Adderall (Stimulants)

Not a prescribing recommendation. This page is educational information about pharmacogenomic research and clinical guidelines - it is not medical or dosing advice, and not a prediction of how any medication will work for you. Never start, stop, or change a medication or dose based on it; talk to your doctor or pharmacist, who can order clinical-grade testing if appropriate.

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Content updated September 2026.

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