Mirtazapine Sandoz Ltd (Mirtazapine)

• Mirtazapine is indicated for the treatment of depressive disorders, acting primarily on the neurochemical pathways involved in mood regulation and emotional processing.
• Major depressive disorder (initial therapy): reduces core depressive symptoms—including persistent sadness, loss of interest, sleep disturbances, and cognitive slowing—thereby improving daily functioning and quality of life in adult patients diagnosed with this condition.
• Major depressive disorder (adjunctive therapy): may be added when response to first‑line antidepressants is inadequate, providing additional symptom relief and supporting remission.

• Mirtazapine antagonizes central presynaptic α2‑adrenergic receptors, which enhances the release of norepinephrine and serotonin. It also blocks postsynaptic 5‑HT2 and 5‑HT3 receptors and histamine H1 receptors, leading to increased serotonergic neurotransmission and sedation, contributing to its antidepressant and anxiolytic effects.

Mirtazapine is associated with a range of adverse reactions that vary in frequency and severity.

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
• Seizures
• Severe hypersensitivity reactions (e.g., Stevens‑Johnson syndrome)
• Suicidal thoughts, especially early in treatment
• Hepatic dysfunction or jaundice
• Leukopenia or thrombocytopenia

• When prescribing or dispensing mirtazapine, several safety considerations should be observed.
• Assess hepatic function before initiating: monitor baseline liver enzymes and repeat as clinically indicated.
• Monitor weight and metabolic parameters: the drug can cause significant appetite increase and weight gain.
• Caution in patients with cardiovascular disease: orthostatic hypotension may occur, especially at treatment initiation.
• Avoid abrupt discontinuation: tapering is recommended to reduce the risk of withdrawal symptoms.
• Pregnancy and lactation: use only if the potential benefit justifies the potential risk to the fetus or infant.
• Store at ambient temperature: keep in the original container, protect from moisture and light.

Mirtazapine may interact with other medicines, requiring careful management.

Major Interactions (Avoid)

• MAO inhibitors: concurrent use can precipitate hypertensive crisis.
• CNS depressants (alcohol, benzodiazepines): additive sedation and respiratory depression.
• Potent CYP2D6 inhibitors (e.g., fluoxetine, paroxetine): may increase mirtazapine plasma concentrations.

Moderate Interactions (Monitor Closely)

• CYP3A4 inducers (rifampin, carbamazepine): may reduce therapeutic efficacy.
• Other serotonergic agents (SSRIs, SNRIs, tramadol): increased risk of serotonin syndrome.
• Anticholinergic drugs: may exacerbate dry mouth and constipation.