Mirtazapin Krka (Mirtazapine)

Mirtazapine acts as an antidepressant within the NaSSA class, targeting depressive disorders.

• Major depressive disorder: alleviates depressive symptoms and improves mood in adults.
• Depressive episodes associated with bipolar disorder: may be used as an adjunct to stabilize mood under specialist supervision.
• Treatment‑resistant depression: considered when first‑line agents are ineffective, under careful clinical evaluation.

• Mirtazapine antagonizes central presynaptic α2‑adrenergic receptors, enhancing noradrenergic release, and blocks 5‑HT2, 5‑HT3 and H1 receptors, which together increase serotonergic and noradrenergic neurotransmission while providing antihistaminic effects that contribute to its therapeutic profile.

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

Common Side Effects

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

Serious or Rare Side Effects

• Agranulocytosis or severe neutropenia
• Stevens‑Johnson syndrome or toxic epidermal necrolysis
• Suicidal thoughts or behavior, especially early in treatment
• Seizures
• Hepatic dysfunction
• Severe allergic reactions (anaphylaxis)

Before initiating therapy, clinicians should evaluate patient history and monitor for specific risks.

• Monitor weight: watch for significant gain and metabolic changes.
• Assess mood: watch for emergence of suicidal ideation, especially in early treatment.
• Evaluate liver function: consider baseline tests in patients with hepatic disease.
• Caution with CNS depressants: avoid excessive sedation when combined with alcohol or benzodiazepines.
• Store below 25°C: keep in the original pack, protect from moisture and direct sunlight.

Mirtazapine can interact with several drug classes, requiring careful management.

Major Interactions (Avoid)

• Monoamine oxidase inhibitors (MAOIs): risk of hypertensive crisis.
• Other serotonergic agents (e.g., SSRIs, SNRIs, tramadol): potential serotonin syndrome.
• CNS depressants (e.g., alcohol, benzodiazepines): enhanced sedation.
• CYP2D6 inhibitors (e.g., fluoxetine, paroxetine): increased mirtazapine plasma levels.
• Anticholinergic drugs: additive anticholinergic burden.

Moderate Interactions (Monitor Closely)

• Antihypertensives: possible additive hypotensive effect.
• Carbamazepine: may reduce mirtazapine concentrations.
• Warfarin: monitor INR for possible alteration.
• Anticonvulsants: may affect seizure threshold.
• Herbal supplements (e.g., St. John’s wort): could modify serotonergic activity.