Mirtazapin Ametas (Mirtazapine)

Mirtazapine is a NaSSA antidepressant that acts on noradrenergic and serotonergic pathways to treat depressive disorders.

• Major depressive disorder: reduces depressive symptoms and improves overall mood in adult patients.
• Acute depressive episodes associated with major depressive disorder: facilitates remission of severe depressive symptoms.
• Treatment-resistant depression (as adjunct therapy): may be considered when first‑line antidepressants are insufficient.

• Mirtazapine antagonizes central presynaptic α2‑adrenergic receptors, increasing norepinephrine release, and blocks postsynaptic 5‑HT2 and 5‑HT3 receptors while antagonizing H1 histamine receptors. This combined action enhances serotonergic and noradrenergic neurotransmission and produces sedative and anxiolytic effects that contribute to its antidepressant efficacy. By reducing inhibitory feedback on noradrenergic neurons and modulating serotonin receptor subtypes, it leads to increased synaptic concentrations of key mood‑regulating neurotransmitters, thereby improving depressive symptoms.

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

Common Side Effects

• Drowsiness: feeling of sleepiness or fatigue.
• Increased appetite: heightened hunger leading to weight gain.
• Dry mouth: reduced salivation causing oral discomfort.
• Constipation: slowed gastrointestinal motility.

Serious or Rare Side Effects

• Agranulocytosis: severe reduction in white blood cells.
• Seizures: occurrence of convulsive episodes.
• Suicidal thoughts: emergence or worsening of suicidal ideation.

When prescribing mirtazapine, clinicians should consider several precautionary measures to ensure patient safety.

• Assess psychiatric history: evaluate for prior suicidal behavior or severe depression.
• Monitor weight: watch for rapid weight gain due to increased appetite.
• Evaluate hepatic function: adjust use in patients with liver impairment.
• Caution in elderly: increased risk of sedation and falls.
• Avoid abrupt discontinuation: taper dose to reduce withdrawal symptoms.
• Store at ambient temperature: keep below 25 °C in the original container, protected from moisture.

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

Major Interactions (Avoid)

• MAO inhibitors: risk of hypertensive crisis; must be discontinued at least 14 days prior.
• CNS depressants: additive sedation and respiratory depression.
• CYP2D6 inhibitors (e.g., fluoxetine, paroxetine): increase mirtazapine plasma levels.

Moderate Interactions (Monitor Closely)

• Anticholinergic agents: may exacerbate dry mouth and constipation.
• Alcohol: enhances sedative effects.
• Warfarin: possible alteration of INR, requiring monitoring.