Mirtazapin Abz (Mirtazapine)

Mirtazapine acts within the central nervous system to alleviate depressive symptoms and is indicated for the following condition:

• Major depressive disorder: improves mood, sleep, appetite and overall functional capacity in adults.

• Mirtazapine blocks central presynaptic α2‑adrenergic receptors, increasing norepinephrine release, and antagonizes 5‑HT2 and 5‑HT3 receptors, which enhances serotonergic neurotransmission while reducing serotonergic side‑effects. This combined action leads to a net increase in mood‑regulating neurotransmitters.

Mirtazapine may cause a range of adverse reactions.

Common Side Effects

• Sedation or drowsiness: feeling unusually sleepy, especially at treatment onset.
• Increased appetite and weight gain: heightened hunger leading to gradual weight increase.
• Dry mouth: reduced salivation causing oral discomfort.
• Constipation: slower intestinal motility.
• Dizziness: light‑headed sensation, particularly when standing quickly.
• Fatigue: general lack of energy.

Serious or Rare Side Effects

• Agranulocytosis or neutropenia: markedly reduced white blood cells, increasing infection risk.
• Severe hypersensitivity reactions: rash, swelling, or difficulty breathing.
• Serotonin syndrome: agitation, hyperthermia, muscle rigidity when combined with other serotonergic agents.
• Suicidal thoughts or behavior: emergence of new or worsening suicidal ideation.
• Hepatotoxicity: abnormal liver function tests.
• Orthostatic hypotension: sudden drop in blood pressure upon standing.

Before initiating therapy, clinicians should consider several safety measures.

• Monitor weight: track changes due to increased appetite.
• Assess suicidal risk: evaluate mood and thoughts regularly, especially early in treatment.
• Use caution in hepatic impairment: adjust dose if liver function is compromised.
• Avoid abrupt discontinuation: taper gradually to reduce withdrawal symptoms.
• Review concomitant CNS depressants: assess additive sedation risk.
• Store at room temperature: keep in original packaging, protect from moisture and direct sunlight.

Mirtazapine can interact with other medicines, requiring attention to avoid adverse outcomes.

Major Interactions (Avoid)

• Monoamine oxidase inhibitors (MAOIs): risk of serotonin syndrome.
• Other serotonergic agents (e.g., SSRIs, SNRIs, tramadol): heightened serotonin toxicity.
• Central nervous system depressants (e.g., benzodiazepines, alcohol): excessive sedation.

Moderate Interactions (Monitor Closely)

• CYP3A4 inhibitors (e.g., ketoconazole) or inducers (e.g., rifampicin): may alter plasma levels.
• Antihypertensive drugs: potential additive blood‑pressure lowering effect.
• Anticholinergic medications: may increase anticholinergic burden and dry mouth.