Mirtazapin Ct (Mirtazapine)

Mirtazapine is indicated for depressive disorders and related conditions where enhancement of noradrenergic and serotonergic neurotransmission is desired.

• Major depressive disorder: reduces depressive symptoms and improves overall mood in adult patients.
• Depressive episodes in bipolar disorder (adjunct): helps alleviate depressive phases when used alongside mood stabilizers.
• Depression with prominent insomnia or loss of appetite: improves sleep quality and stimulates appetite, addressing common associated symptoms.

• Mirtazapine acts as an antagonist at central presynaptic α2‑adrenergic receptors, increasing the release of norepinephrine and serotonin. It also selectively blocks postsynaptic 5‑HT2 and 5‑HT3 receptors while sparing 5‑HT1A, which enhances serotonergic transmission and contributes to its antidepressant and anxiolytic effects. The combined effect results in heightened mood, reduced anxiety, and improved sleep architecture, while the antihistaminic activity at H1 receptors adds to its sedative properties.

Mirtazapine may cause a range of adverse reactions, which are generally categorized by 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
• Hepatotoxicity or abnormal liver function tests
• Seizures
• Suicidal thoughts or worsening depression
• Stevens‑Johnson syndrome or toxic epidermal necrolysis
• Severe hypersensitivity reactions (anaphylaxis)

When prescribing mirtazapine, clinicians should evaluate several safety considerations to minimize risk.

• Assess hepatic function: adjust use in patients with liver impairment.
• Monitor weight and metabolic parameters: due to risk of weight gain.
• Evaluate for suicidal ideation: especially during initial treatment or dose changes.
• Use caution in the elderly: increased sensitivity to sedation and falls.
• Avoid abrupt discontinuation: taper gradually to reduce withdrawal symptoms.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Mirtazapine can interact with other medicines, altering its effectiveness or increasing toxicity.

Major Interactions (Avoid)

• Monoamine oxidase inhibitors (MAOIs): risk of serotonin syndrome.
• Other serotonergic antidepressants (SSRIs, SNRIs): increased serotonin toxicity.
• Alcohol or CNS depressants: additive sedation and respiratory depression.

Moderate Interactions (Monitor Closely)

• Strong CYP2D6/CYP3A4 inhibitors (e.g., fluoxetine, ketoconazole): raise mirtazapine levels.
• Anticoagulants such as warfarin: may affect INR.
• Anticonvulsants like carbamazepine: may lower mirtazapine concentrations.