Mirtazapina Sandoz Farmacéutica (Mirtazapine)

Mirtazapine is indicated for depressive disorders and related conditions.

• Major depressive disorder: alleviates depressive symptoms and improves mood in adults.
• Treatment‑resistant depression: provides an alternative mechanism when first‑line agents are ineffective.
• Depression with prominent insomnia: helps improve sleep quality while treating depressive symptoms.

• Mirtazapine acts as an antagonist at central presynaptic α2‑adrenergic receptors, increasing norepinephrine release, and selectively blocks serotonin 5‑HT2 and 5‑HT3 receptors while strongly antagonising histamine H1 receptors. This combined activity enhances noradrenergic and serotonergic neurotransmission, contributing to its antidepressant and anxiolytic effects.

Mirtazapine may cause a range of adverse reactions.

Common Side Effects

• Sedation or drowsiness: often pronounced at treatment initiation.
• Increased appetite and weight gain: may be significant with prolonged use.
• Dry mouth, constipation, or dizziness: typical anticholinergic‑like symptoms.

Serious or Rare Side Effects

• Agranulocytosis or severe neutropenia: requires immediate medical attention.
• Suicidal thoughts or behavior: especially during early therapy.
• Severe hypersensitivity reactions: including rash, angioedema, or anaphylaxis.
• Hepatic dysfunction or jaundice: monitor liver enzymes if clinically indicated.
• Seizures: rare but reported, particularly in predisposed individuals.

Before initiating therapy, consider the following precautions.

• Assess hepatic function: adjust use in severe liver impairment.
• Monitor weight: due to potential for significant weight gain.
• Evaluate for suicidal ideation: especially during the first weeks of treatment.
• Caution in elderly patients: increased risk of sedation, falls, and confusion.
• Avoid abrupt discontinuation: taper the dose to prevent withdrawal symptoms.
• Store at ambient temperature: keep in the original container, protect from moisture and light.

Mirtazapine can interact with several drug classes.

Major Interactions (Avoid)

• Monoamine oxidase inhibitors (MAOIs): risk of hypertensive crisis.
• Other central nervous system depressants (e.g., alcohol, benzodiazepines): additive sedation.
• Strong CYP2D6 inhibitors (e.g., fluoxetine, paroxetine): may increase mirtazapine plasma levels.
• Serotonergic agents (e.g., SSRIs, SNRIs, tramadol): heightened risk of serotonin syndrome.

Moderate Interactions (Monitor Closely)

• CYP3A4 inducers (e.g., carbamazepine, phenytoin): may reduce efficacy.
• Antihypertensive drugs: potential for enhanced hypotensive effect.
• Anticholinergic medications: additive anticholinergic burden may worsen dry mouth or constipation.