Mirtazapine

NaSSA·Psychiatry - Antidepressants

Major Depressive Disorder

PBSNaSSAAvanza, Remeron, Mirtazapine ODT45 mg tabletS4+1

Max Dose

45 mg/day

Half-life

20–40 h

Sedation

HIGH @ LOW DOSE

Weight Gain

HIGH RISK

Rapid Summary

Overview

Noradrenergic and Specific Serotonergic Antidepressant (NaSSA). Unique dual-action drug. Highly sedating and strongly stimulates appetite. Zero sexual side effects.

Maximum Dose

Max 45 mg/day.

Clinical Focus

Displays an inverse dose-sedation relationship. 15mg puts you to sleep. 45mg keeps you awake.

Bottom Line

Mirtazapine is a sedating antidepressant ideal for depression with insomnia and poor appetite, but causes significant weight gain and sedation that may limit long-term tolerability.

Formulation & Access

Brand Names

Avanza, Remeron, Mirtazapine ODT

Oral Routes

Tablets (15, 30, 45 mg). ODT Wafers (dissolve on tongue).

Prescribing & PBS

Unrestricted General Benefit (S4).

Indications & Use

Primary

PBSTGA

Major Depressive Disorder.

Off-Label

OFF

Severe insomnia, appetite stimulation in cancer/anorexia, prevention of nausea.

Clinical Place

The gold-standard antidepressant for an elderly patient who is depressed, not eating, losing weight, and not sleeping. Kills three birds with one stone.

Quick reference

Class & Role

NaSSA — Noradrenergic and Specific Serotonergic Antidepressant (NaSSA).

Route / Formulation

Tablets (15, 30, 45 mg). ODT Wafers (dissolve on tongue). (Avanza, Remeron, Mirtazapine ODT)

Usual Dose & Max

Start PO 15 mg NOCTE. Titrate to 30 mg or 45 mg for antidepressant effect. Max 45 mg/day.

Key Indication Doses

Depression / Insomnia: Start PO 15 mg NOCTE. Titrate to 30 mg or 45 mg for antidepressant effect. Frail / Underweight Elderly: Start PO 15 mg NOCTE. (Used strategically to promote weight gain and sleep).

Best Uses

Mirtazapine is a sedating antidepressant ideal for depression with insomnia and poor appetite, but causes significant weight gain and sedation that may limit long-term tolerability.

Avoid / Cautions

Concurrent use of MAOIs. Pregnancy Category B3. Very safe regarding sexual dysfunction (does not cause it).

Key Risks

Metabolic: Massive appetite stimulation, severe weight gain (can be 10+ kg in a few months). Neurological: Profound sedation, hangover effect, dizziness. Haematological: RARE — Agranulocytosis or neutropenia (must check FBC if patient develops sudden fever/sore throat).

Key Interactions

Additive sedation with alcohol, benzos, and opioids. Less risk of Serotonin Syndrome than SSRIs, but still a risk if combined with Tramadol or MAOIs.

Monitoring

Baseline and routine Weight, BSL, and Lipids. Ensure weight gain is not pushing patient into metabolic syndrome. Ask about sore throat (agranulocytosis risk).

Clinical Pearl

At 15mg, Mirtazapine's antihistamine (sedating) effect dominates. At 30mg and 45mg, the massive noradrenaline release overrides the histamine blockade, making the drug *activating*. If a patient on 15mg is too sedated during the day, paradoxically increasing the dose to 30mg will wake them up.

Access

Avanza, Remeron, Mirtazapine ODT45 mg tablet

Brand: Avanza, Remeron, Mirtazapine ODT
Formulation: Tablets (15, 30, 45 mg)

Mirtazapine

NaSSA·Psychiatry - Antidepressants

Major Depressive Disorder

PBSNaSSAAvanza, Remeron, Mirtazapine ODT45 mg tabletS4+1

Max Dose

45 mg/day

Half-life

20–40 h

Sedation

HIGH @ LOW DOSE

Weight Gain

HIGH RISK

Rapid Summary

Overview

Noradrenergic and Specific Serotonergic Antidepressant (NaSSA). Unique dual-action drug. Highly sedating and strongly stimulates appetite. Zero sexual side effects.

Maximum Dose

Max 45 mg/day.

Clinical Focus

Displays an inverse dose-sedation relationship. 15mg puts you to sleep. 45mg keeps you awake.

Bottom Line

Mirtazapine is a sedating antidepressant ideal for depression with insomnia and poor appetite, but causes significant weight gain and sedation that may limit long-term tolerability.

Formulation & Access

Brand Names

Avanza, Remeron, Mirtazapine ODT

Oral Routes

Tablets (15, 30, 45 mg). ODT Wafers (dissolve on tongue).

Prescribing & PBS

Unrestricted General Benefit (S4).

Indications & Use

Primary

PBSTGA

Major Depressive Disorder.

Off-Label

OFF

Severe insomnia, appetite stimulation in cancer/anorexia, prevention of nausea.

Clinical Place

The gold-standard antidepressant for an elderly patient who is depressed, not eating, losing weight, and not sleeping. Kills three birds with one stone.

Quick reference

Class & Role

NaSSA — Noradrenergic and Specific Serotonergic Antidepressant (NaSSA).

Route / Formulation

Tablets (15, 30, 45 mg). ODT Wafers (dissolve on tongue). (Avanza, Remeron, Mirtazapine ODT)

Usual Dose & Max

Start PO 15 mg NOCTE. Titrate to 30 mg or 45 mg for antidepressant effect. Max 45 mg/day.

Key Indication Doses

Best Uses

Mirtazapine is a sedating antidepressant ideal for depression with insomnia and poor appetite, but causes significant weight gain and sedation that may limit long-term tolerability.

Avoid / Cautions

Concurrent use of MAOIs. Pregnancy Category B3. Very safe regarding sexual dysfunction (does not cause it).

Key Risks

Key Interactions

Additive sedation with alcohol, benzos, and opioids. Less risk of Serotonin Syndrome than SSRIs, but still a risk if combined with Tramadol or MAOIs.

Monitoring

Baseline and routine Weight, BSL, and Lipids. Ensure weight gain is not pushing patient into metabolic syndrome. Ask about sore throat (agranulocytosis risk).

Clinical Pearl

Access

Avanza, Remeron, Mirtazapine ODT45 mg tablet

Brand: Avanza, Remeron, Mirtazapine ODT
Formulation: Tablets (15, 30, 45 mg)