Mirtazapine Aurobindo (Mirtazapine)

Mirtazapine is a NaSSA‑type antidepressant that modulates noradrenergic and serotonergic pathways to treat depressive disorders.

• Major depressive disorder: reduces depressive symptoms and improves overall mood in adults.
• Treatment‑resistant depression: may be added when first‑line antidepressants have not achieved adequate response.
• Depression with insomnia: helps alleviate sleep disturbances associated with depressive episodes.

• Mirtazapine acts as an antagonist at central presynaptic α2‑adrenergic receptors, which disinhibits norepinephrine release. It also blocks postsynaptic 5‑HT2 and 5‑HT3 receptors and strongly antagonizes histamine H1 receptors. These combined actions increase norepinephrine and serotonin neurotransmission while producing sedative and appetite‑stimulating effects, contributing to its antidepressant efficacy. The antagonism at 5‑HT2 and 5‑HT3 receptors reduces anxiety and gastrointestinal side effects, while H1 blockade accounts for the characteristic sedation and weight gain observed with therapy.

Mirtazapine may cause a range of adverse reactions, which are categorized by frequency.

Common Side Effects

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

Serious or Rare Side Effects

• Agranulocytosis or severe neutropenia
• Serotonin syndrome, especially with other serotonergic drugs
• Severe hypotension or syncope
• Seizures
• Suicidal thoughts or worsening depression
• Hepatotoxicity (rare)

Before initiating therapy, clinicians should evaluate several safety considerations.

• Assess hepatic function: adjust dose or avoid use in severe liver impairment.
• Monitor body weight: anticipate possible weight gain and counsel on nutrition.
• Screen for suicidal ideation: particularly during the first weeks of treatment.
• Use caution in elderly patients: increased risk of sedation, falls and orthostatic hypotension.
• Avoid abrupt discontinuation: taper the dose to reduce withdrawal symptoms.
• Store at ambient temperature: keep in the original container, protect from moisture and light.

Mirtazapine can interact with other medicines, and some combinations require avoidance while others need close monitoring.

Major Interactions (Avoid)

• Monoamine oxidase inhibitors (MAOIs): risk of severe hypertension or serotonin syndrome.
• Other serotonergic agents (e.g., SSRIs, SNRIs, tramadol): increase risk of serotonin syndrome.
• Central nervous system depressants (e.g., benzodiazepines, alcohol): additive sedation and respiratory depression.
• Strong CYP2D6 inhibitors (e.g., fluoxetine, paroxetine): raise mirtazapine plasma concentrations.
• Alcohol: may enhance sedative effects and impair cognition.

Moderate Interactions (Monitor Closely)

• Antihypertensive drugs: additive hypotensive effect.
• Anticholinergic medications: may exacerbate anticholinergic burden.
• Carbamazepine or other enzyme inducers: may reduce mirtazapine effectiveness.
• Lithium: monitor for increased sedation.
• Oral contraceptives: possible alteration of hormone levels, monitor efficacy.