Mirtazapine Grindeks (Mirtazapine)

Mirtazapine is indicated for depressive disorders and works by modulating noradrenergic and serotonergic pathways.

• Major depressive disorder: reduces depressive symptoms and improves daily functioning.
• Depressive episodes in bipolar disorder (adjunct): may lessen the severity of the depressive phase when added to mood stabilisers.
• Depression with comorbid anxiety: helps alleviate mood symptoms while also addressing associated anxiety features.

• Mirtazapine antagonises central presynaptic α2‑adrenergic receptors, which increases norepinephrine release, and blocks postsynaptic 5‑HT2 and 5‑HT3 receptors, enhancing serotonergic transmission. It also inhibits histamine H1 receptors, contributing to its sedative and appetite‑stimulating effects.

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 or light‑headedness
• Peripheral edema

Serious or Rare Side Effects

• Agranulocytosis or severe neutropenia
• Suicidal thoughts or behaviour, especially early in treatment
• Serotonin syndrome when combined with other serotonergic agents
• Severe hypotension or orthostatic collapse
• Hepatic dysfunction or jaundice
• Extrapyramidal symptoms (rare).

Before initiating therapy, clinicians should evaluate several safety considerations.

• Pregnancy: Category C; discuss potential risks and benefits with the prescriber.
• Breastfeeding: weigh maternal benefit against possible infant exposure.
• Elderly patients: monitor for excessive sedation, falls, and weight gain.
• History of bipolar disorder: assess risk of switching to mania or hypomania.
• Concomitant CNS depressants: may potentiate sedation and respiratory depression.
• Store at ambient temperature below 25°C: keep in the original container, 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 or serotonin syndrome.
• Linezolid or other reversible MAO inhibitors: similar serotonin toxicity risk.
• Other serotonergic agents (e.g., SSRIs, SNRIs, tramadol): may precipitate serotonin syndrome.
• Carbamazepine: induces metabolism, reducing mirtazapine plasma levels.
• Strong CYP3A4 inducers (e.g., rifampicin): may lower efficacy.

Moderate Interactions (Monitor Closely)

• CNS depressants or alcohol: enhanced sedative effect.
• Antihypertensive drugs: additive blood pressure lowering.
• CYP2D6 inhibitors (e.g., fluoxetine): may increase mirtazapine concentrations.
• Warfarin: potential alteration of INR, monitor coagulation.
• Anticholinergic agents: may worsen dry mouth and constipation.