Mirtor (Mirtazapine)

Mirtazapine is indicated for major depressive disorder, a condition that affects mood, cognition and daily functioning.

• Major depressive disorder: alleviates depressive symptoms and improves overall mood and functional capacity.

• Mirtazapine acts as an antagonist at central presynaptic α2‑adrenergic receptors, which disinhibits norepinephrine release, and blocks 5‑HT2 and 5‑HT3 serotonergic receptors, enhancing serotonergic neurotransmission. It also antagonizes H1 histamine receptors, contributing to its sedative properties. The combined actions increase noradrenergic and serotonergic activity, addressing the neurochemical deficits associated with depression.

Mirtazapine may cause a range of adverse reactions that vary in frequency and severity.

Common Side Effects

• Sedation: feeling unusually sleepy or drowsy.
• Increased appetite: heightened desire for food, often leading to weight gain.
• Weight gain: noticeable increase in body weight.
• Dry mouth: reduced salivation causing discomfort.
• Constipation: infrequent or difficult bowel movements.
• Dizziness: sensation of light‑headedness or unsteadiness.

Serious or Rare Side Effects

• Agranulocytosis: severe reduction in white blood cells.
• Severe neutropenia: markedly low neutrophil count.
• Serotonin syndrome: potentially life‑threatening condition with agitation, hyperthermia, and neuromuscular abnormalities.
• Suicidal thoughts: emergence or worsening of suicidal ideation.
• Severe hypotension: marked drop in blood pressure causing faintness.
• Hepatic dysfunction: abnormal liver enzyme elevations or liver injury.

Before initiating therapy with Mirtor, clinicians should consider several safety measures.

• Assess hepatic function: evaluate liver enzymes and function tests.
• Monitor weight: track changes due to increased appetite.
• Evaluate for suicidal ideation: especially during early treatment.
• Avoid abrupt discontinuation: taper gradually to reduce withdrawal risk.
• Caution in elderly: start at low dose and monitor for sedation.
• Store at room temperature: keep in the original pack, protect from moisture.

Mirtor can interact with other medicines, altering its efficacy or safety profile.

Major Interactions (Avoid)

• MAO inhibitors: concurrent use may precipitate serotonin syndrome.
• Other serotonergic agents (e.g., SSRIs, SNRIs, tramadol): increase risk of serotonin syndrome.
• Carbamazepine: induces metabolism, reducing mirtazapine levels.
• Fluoxetine or other strong CYP2D6 inhibitors: raise mirtazapine concentrations.

Moderate Interactions (Monitor Closely)

• Alcohol: may enhance central nervous system depression.
• CNS depressants (e.g., benzodiazepines, antihistamines): increase sedation.
• Antihypertensives: additive blood‑pressure‑lowering effect.
• Oral contraceptives: possible alteration of hormone levels.