Mirtazapina Generis (Mirtazapine)

Mirtazapine is used within the antidepressant class to address mood disorders and related symptoms.

• Major depressive disorder: alleviates depressive symptoms and improves sleep quality.
• Depressive episodes in major depressive disorder: provides a rapid onset of antidepressant effect.
• Adjunctive therapy for major depressive disorder with inadequate response: enhances overall treatment response when other antidepressants are insufficient.

• Mirtazapine acts as an antagonist at central presynaptic α2‑adrenergic receptors, which increases norepinephrine release. It also blocks 5‑HT2 and 5‑HT3 serotonin receptors and H1 histamine receptors, resulting in enhanced serotonergic and noradrenergic neurotransmission while producing sedative and appetite‑stimulating effects.

Mirtazapine may cause a range of adverse reactions that vary in frequency and severity.

Common Side Effects

• Sedation: drowsiness, especially at treatment initiation.
• Increased appetite: often leading to weight gain.
• Dry mouth: reduced salivation.
• Constipation: slowed gastrointestinal motility.
• Dizziness: light‑headedness on standing.
• Orthostatic hypotension: mild blood pressure drop upon standing.

Serious or Rare Side Effects

• Agranulocytosis: severe reduction in white blood cells.
• Hepatic dysfunction: elevated liver enzymes or hepatitis.
• Severe hypersensitivity: rash, angioedema, or anaphylaxis.
• Suicidal ideation: emergence of suicidal thoughts, particularly early in therapy.
• Serotonin syndrome: rare when combined with other serotonergic agents.
• Hematologic abnormalities: neutropenia or thrombocytopenia.

Before prescribing Mirtazapine, clinicians should consider several safety aspects.

• Monitor weight: patients may experience increased appetite and weight gain.
• Assess for suicidal thoughts: especially during the first weeks of treatment.
• Evaluate hepatic function: use caution in patients with liver disease.
• Review concomitant CNS depressants: increased sedation risk.
• Consider pregnancy status: safety data are limited; weigh risks and benefits.
• Store below 25°C: keep in the original pack, protect from moisture.

Mirtazapine can interact with other medicines, requiring careful management.

Major Interactions (Avoid)

• MAO inhibitors: risk of hypertensive crisis and serotonin syndrome.
• Other CNS depressants (e.g., benzodiazepines, alcohol): may cause excessive sedation.
• Strong CYP2D6 inhibitors: can increase mirtazapine plasma levels.

Moderate Interactions (Monitor Closely)

• CYP3A4 inducers (e.g., carbamazepine): may reduce efficacy.
• Antihypertensive agents: additive hypotensive effect.
• Anticholinergic drugs: may worsen dry mouth and constipation.
• Other antidepressants: monitor for additive serotonergic effects.