Mirtazapina Aristo (Mirtazapine)

Mirtazapine is a NaSSA antidepressant that acts on neurotransmitter pathways involved in mood regulation.

• Major depressive disorder: reduces depressive symptoms and improves overall mood in adult patients.
• Depression with insomnia: promotes sleep continuity and may increase appetite, supporting recovery.
• Depression with anxiety features: can alleviate co‑existing anxiety symptoms associated with depressive episodes.

• Mirtazapine blocks central presynaptic α2‑adrenergic receptors, enhancing the release of norepinephrine and serotonin. It also antagonizes postsynaptic 5‑HT2 and 5‑HT3 receptors while strongly inhibiting histamine H1 receptors. This combined action increases noradrenergic and serotonergic neurotransmission and produces sedative and appetite‑stimulating effects that contribute to its antidepressant activity. The drug’s affinity for these receptors reduces the inhibitory feedback on monoamine release, leading to a net increase in synaptic concentrations of key mood‑regulating neurotransmitters.

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

Common Side Effects

• Sedation or drowsiness
• Increased appetite and weight gain
• Dry mouth
• Dizziness

Serious or Rare Side Effects

• Agranulocytosis or severe neutropenia
• Severe hypersensitivity reactions (rash, angioedema, anaphylaxis)
• Seizures
• Suicidal thoughts or behavior, especially early in treatment

When prescribing mirtazapine, clinicians should consider several safety aspects.

• Dose titration: start with a low dose and adjust under medical supervision to minimize sedation.
• Hepatic impairment: use cautiously, as metabolism may be reduced.
• Renal impairment: monitor patients with severe kidney dysfunction.
• Pregnancy and lactation: avoid unless benefits outweigh potential risks, due to limited data.
• Elderly patients: increased sensitivity to sedation and weight gain; monitor closely.
• Store at ambient temperature: keep in original packaging, protect from moisture and light.

Mirtazapine interacts with several drug classes; careful assessment is required.

Major Interactions (Avoid)

• MAO inhibitors: concurrent use can cause hypertensive crisis or serotonin syndrome.
• CNS depressants (e.g., benzodiazepines, opioids): additive sedation and respiratory depression.
• Alcohol: enhances sedative effects and may impair cognition.

Moderate Interactions (Monitor Closely)

• SSRIs, SNRIs, or other serotonergic agents: increased risk of serotonin syndrome.
• Anticholinergic drugs: may exacerbate dry mouth and constipation.
• CYP2D6 inhibitors (e.g., fluoxetine, paroxetine): can raise mirtazapine plasma levels.