Mirtazapina Psidep 30 Mg Comprimidos Revestidos (Mirtazapine)

Mirtazapine is an antidepressant that acts on noradrenergic and serotonergic pathways, primarily indicated for the following conditions:

• Major depressive disorder: reduces depressive symptoms and improves overall functioning in adults.
• Treatment‑resistant depression: may be added when first‑line antidepressants are insufficient.
• Depression in the elderly: helps with mood, sleep and appetite disturbances common in older patients.

• Mirtazapine blocks central presynaptic α2‑adrenergic receptors, increasing norepinephrine release, and antagonizes 5‑HT2 and 5‑HT3 receptors while acting as a partial agonist at 5‑HT1A receptors. This combined activity enhances serotonergic and noradrenergic neurotransmission, leading to antidepressant and anxiolytic effects without significant inhibition of serotonin reuptake. The net result is a balanced modulation of mood‑regulating circuits, contributing to improved sleep and appetite, while its antihistaminic and anticholinergic properties may add to sedation and weight gain.

Mirtazapine may cause a range of adverse reactions, which are grouped by frequency and severity.

Common Side Effects

• Sedation: drowsiness, especially at treatment initiation.
• Increased appetite/weight gain: notable in many patients.
• Dry mouth: reduced salivation.
• Constipation: slowed gastrointestinal motility.
• Dizziness: orthostatic light‑headedness.
• Orthostatic hypotension: drop in blood pressure upon standing.

Serious or Rare Side Effects

• Agranulocytosis: severe reduction in white blood cells.
• Seizures: rare but possible convulsive events.
• Severe neutropenia: marked decrease in neutrophil count.
• Hepatotoxicity: liver enzyme elevations or injury.
• Suicidal ideation: emergence of suicidal thoughts, particularly early in therapy.
• Serotonin syndrome: when combined with other serotonergic agents.

When prescribing mirtazapine, clinicians should consider several safety precautions to minimize risk.

• Assess hepatic function: adjust use in patients with severe liver impairment.
• Monitor for suicidal thoughts: especially during the first weeks of treatment.
• Caution in elderly: increased risk of sedation, falls and orthostatic hypotension.
• Avoid abrupt discontinuation: taper to reduce withdrawal symptoms.
• Pregnancy and lactation: safety not established; use only if benefit outweighs potential risk.
• Store at ambient temperature: keep in the original pack, protect from moisture.

Mirtazapine interacts with several medicines; awareness of the interaction level guides clinical management.

Major Interactions (Avoid)

• MAO inhibitors: risk of hypertensive crisis.
• CYP2D6 inhibitors (e.g., fluoxetine): increased mirtazapine plasma levels.
• Other CNS depressants (e.g., alcohol, benzodiazepines): enhanced sedation.
• Serotonergic agents (e.g., SSRIs, SNRIs, tramadol): potential serotonin syndrome.
• QT‑prolonging drugs: additive cardiac risk.

Moderate Interactions (Monitor Closely)

• CYP3A4 inducers (e.g., carbamazepine): reduced efficacy.
• Anticholinergic drugs: additive dry‑mouth effects.
• Antihistamines: increased sedation.
• Lithium: monitor lithium serum concentrations.
• Warfarin: monitor INR for possible anticoagulation changes.