Mirtazapin-Ct Abz (Mirtazapine)

Mirtazapine belongs to the NaSSA class and is used to manage depressive disorders.

• Major depressive disorder: alleviates depressive symptoms and improves mood in adult patients.
• Depressive episodes associated with major depressive disorder: reduces severity and frequency of episodes.
• Treatment‑resistant depression (as adjunct): may enhance response when other antidepressants are insufficient.

• Mirtazapine acts as an antagonist at central presynaptic α2‑adrenergic receptors, which increases norepinephrine release, and blocks postsynaptic 5‑HT2 and 5‑HT3 receptors, enhancing serotonergic transmission. It also potently antagonizes histamine H1 receptors, contributing to its sedative and appetite‑stimulating effects, while sparing 5‑HT1A receptors, which helps improve mood and anxiety symptoms.

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

Common Side Effects

• Sedation or drowsiness: feeling unusually sleepy, especially at treatment initiation.
• Increased appetite and weight gain: notable rise in hunger and body weight.
• Dry mouth: reduced salivation leading to discomfort.
• Constipation: slowed gastrointestinal motility.
• Dizziness: light‑headed sensation, particularly when standing quickly.

Serious or Rare Side Effects

• Agranulocytosis or severe neutropenia: marked reduction in white blood cells.
• Stevens‑Johnson syndrome or toxic epidermal necrolysis: severe skin reactions.
• Suicidal thoughts or behavior: emergence of self‑harm ideation.
• Hepatic dysfunction: abnormal liver enzyme elevations.
• Severe hypotension: marked drop in blood pressure, especially when combined with other depressants.
• Seizures: rare occurrence of convulsive episodes.

When prescribing or dispensing mirtazapine, clinicians should consider several safety measures.

• Monitor weight: track changes due to appetite stimulation.
• Assess for suicidal ideation: especially during early treatment phases.
• Use caution in hepatic impairment: adjust therapy if liver function is compromised.
• Avoid abrupt discontinuation: taper gradually to reduce withdrawal symptoms.
• Review concomitant CNS depressants: evaluate additive sedation risk.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Mirtazapine can interact with other medicines, requiring careful management.

Major Interactions (Avoid)

• Monoamine oxidase inhibitors (MAOIs): risk of hypertensive crisis or serotonin syndrome.
• Potent CYP2D6 inhibitors (e.g., fluoxetine, paroxetine): may increase mirtazapine plasma levels.

Moderate Interactions (Monitor Closely)

• Other CNS depressants (benzodiazepines, alcohol): additive sedation and respiratory depression.
• Selective serotonin reuptake inhibitors (SSRIs) or SNRIs: potential for serotonin syndrome.
• CYP3A4 inhibitors (ketoconazole, erythromycin): may modestly raise mirtazapine concentrations.