Mirtazapina Almus (Mirtazapine)

Mirtazapine is used in the treatment of depressive disorders, acting primarily on noradrenergic and serotonergic pathways.

• Major depressive disorder: reduces depressive symptoms, improves mood, sleep and appetite in adult patients.
• Treatment‑resistant depression: may be added when first‑line antidepressants have insufficient response.
• Depression with insomnia: helps alleviate depressive symptoms while promoting better sleep quality.

• Mirtazapine exerts its antidepressant effect by antagonizing central presynaptic α2‑adrenergic receptors, which enhances the release of norepinephrine and serotonin. It also blocks postsynaptic 5‑HT2 and 5‑HT3 receptors and histamine H1 receptors, leading to increased serotonergic neurotransmission and sedation. The net effect is a rapid improvement in depressive symptoms with a lower risk of sexual dysfunction compared with many selective serotonin reuptake inhibitors.

Mirtazapine may cause a range of adverse reactions, which are generally classified by frequency and severity.

Common Side Effects

• Drowsiness or sedation
• Increased appetite and weight gain
• Dry mouth
• Constipation

Serious or Rare Side Effects

• Severe neutropenia or agranulocytosis
• Hepatotoxicity
• Suicidal thoughts, especially in young adults

When prescribing mirtazapine, clinicians should consider several precautionary measures to ensure safe use.

• Assess psychiatric history: evaluate for bipolar disorder or suicidal ideation before initiating therapy.
• Monitor weight and metabolic parameters: due to risk of weight gain and increased appetite.
• Caution in hepatic impairment: dose adjustment may be required in patients with liver dysfunction.
• Avoid abrupt discontinuation: taper gradually to reduce risk of withdrawal symptoms.
• Use in pregnancy and lactation: only if potential benefit justifies potential risk; discuss with obstetric specialist.
• Store at ambient temperature: keep below 25 °C in the original container, protect from moisture and light.

Mirtazapine can interact with other medicines, altering its efficacy or safety profile.

Major Interactions (Avoid)

• Monoamine oxidase inhibitors (MAOIs): concurrent use can cause hypertensive crisis or serotonin syndrome.
• Potent CYP2D6 inhibitors (e.g., fluoxetine, paroxetine): may increase mirtazapine plasma levels and toxicity.
• CNS depressants (e.g., benzodiazepines, alcohol): additive sedation and respiratory depression.

Moderate Interactions (Monitor Closely)

• Other serotonergic agents (e.g., SSRIs, SNRIs, triptans): increase risk of serotonin syndrome; monitor for symptoms.
• Anticholinergic drugs: may exacerbate dry mouth and constipation.
• Warfarin: possible alteration of INR; monitor coagulation parameters.