Mirzasna (Mirtazapine)

Mirtazapine acts on central neurotransmitter pathways to alleviate depressive symptoms.

• Major depressive disorder: reduces depressive mood, improves sleep and appetite, and enhances overall functioning.

• Mirtazapine antagonizes central presynaptic α2‑adrenergic receptors, leading to increased release of norepinephrine and serotonin. It also blocks postsynaptic 5‑HT2 and 5‑HT3 receptors, which further modulates serotonergic activity and contributes to its antidepressant effect.

Mirtazapine may cause a range of adverse reactions, from mild to severe.

Common Side Effects

• Sedation or drowsiness: feeling unusually sleepy, especially at treatment start.
• Increased appetite and weight gain: heightened hunger leading to weight increase.
• Dry mouth: reduced salivation causing oral discomfort.
• Constipation: slowed gastrointestinal transit.
• Dizziness: light‑headed sensation, particularly when standing quickly.
• Edema: mild swelling of ankles or feet.

Serious or Rare Side Effects

• Agranulocytosis: severe reduction in white blood cells, increasing infection risk.
• Seizures: occurrence of convulsive episodes.
• Severe hypersensitivity: rash, itching, swelling, or difficulty breathing.
• Hepatotoxicity: signs of liver injury such as jaundice.
• Suicidal thoughts: emergence or worsening of suicidal ideation.
• Hyponatremia: low blood sodium causing confusion or weakness.

Before initiating therapy, consider the following safety measures.

• Pregnancy: discuss potential risks with a healthcare professional; data are limited.
• Breastfeeding: evaluate benefits versus risks, as drug may pass into milk.
• Elderly patients: start at lower doses and monitor for sedation and falls.
• Hepatic impairment: dose adjustment may be required; monitor liver function.
• Concomitant CNS depressants: avoid excessive sedation by adjusting doses.
• Store at ambient temperature: keep below 25 °C, retain in original packaging, protect from moisture and direct sunlight.

Mirtazapine can interact with several drug classes, requiring careful management.

Major Interactions (Avoid)

• MAO inhibitors: risk of serotonin syndrome; discontinue MAOI at least 14 days prior.
• CNS depressants (e.g., benzodiazepines, alcohol): may cause profound sedation or respiratory depression.

Moderate Interactions (Monitor Closely)

• Anticoagulants (e.g., warfarin): may enhance bleeding risk; monitor INR.
• CYP2D6 inhibitors (e.g., fluoxetine, paroxetine): can increase mirtazapine plasma levels.
• Anticholinergic agents: additive dry mouth and constipation.
• Lithium: may increase risk of neurotoxicity; monitor lithium levels.