Mirtazapine

Indications
Mirtazapine Tablets are indicated for the treatment of major depressive disorder.
The efficacy of Mirtazapine in the treatment of major depressive disorder was established in 6-week controlled trials of outpatients whose diagnoses corresponded most closely to the Diagnostic and Statistical Manual of Mental Disorders- 3rd edition (DSM-III) category of major depressive disorder
A major depressive episode (DSM-IV) implies a prominent and relatively persistent (nearly every day for at least 2 weeks) depressed or dysphoric mood that usually interferes with daily functioning, and includes at least 5 of the following 9 symptoms: depressed mood, loss of interest in usual activities, significant change in weight and/or appetite, insomnia or hypersomnia, psychomotor agitation or retardation, increased fatigue, feelings of guilt or worthlessness, slowed thinking or impaired concentration, a suicide attempt, or suicidal ideation.
The effectiveness of Mirtazapine in hospitalized depressed patients has not been adequately studied.
The efficacy of Mirtazapine in maintaining a response in patients with major depressive disorder for up to 40 weeks following 8 to 12 weeks of initial open-label treatment was demonstrated in a placebo-controlled trial. Nevertheless, the physician who elects to use Mirtazapine for extended periods should periodically re-evaluate the long-term usefulness of the drug for the individual patient

Therapeutic Class
Atypical anti-depressant drugs

Pharmacology
Mirtazapine, a piperazinoazepine tetracyclic antidepressant, enhances noradrenergic and serotonergic activity through blockade of central presynaptic adrenergic α2-receptors.

Dosage & Administration
Adult: Initially, 15 mg daily; may be increased gradually depending on clinical response. Change dose at intervals of at least 1-2 wk. Usual effective dose: 15-45 mg daily given as single dose, preferably at bedtime, or in 2 divided doses.
Children: Safety and efficacy not established.
Geriatric: Use with caution.

Interaction
Mirtazapine potentiates sedative effects with alcohol or benzodiazepines, increased plasma levels with potent CYP3A4 inhibitors (e.g. HIV-protease inhibitors, azole antifungals including ketoconazole, erythromycin, nefazodone), reduced plasma levels with carbamazepine and other inducers of CYP3A4 and increased bioavailability with cimetidine.

Contraindications
Mirtazapine is contraindicated in patients with hypersensitivity. Do not use with or within 2 weeks of stopping an MAOI; at least 1 week should elapse between discontinuing mirtazapine and initiating any drug which may provoke a serious reaction (e.g. phenelzine)

Side Effects
The most commonly reported adverse effects with mirtazapine are increase in appetite, weight gain, edema, drowsiness or sedation, dizziness, headache etc.

Pregnancy & Lactation
Mirtazapine Should not be used during pregnancy and lactation.

Precautions & Warnings
Mirtazapine should be used cautiously in patients with epilepsy or history of seizure, history of mania /hypomania, patients with hepatic or renal impairment; cardiac disorders e.g. conduction disturbances, angina pectoris, recent MI. Hypotension, DM, psychoses, history of bipolar disorder. Stop treatment if jaundice develops. Monitor patient for signs of bone marrow depression. Monitor patient for suicidal tendency. Avoid abrupt withdrawal. May impair ability to drive or operate machinery.

Overdose Effects
Symptoms: Disorientation, drowsiness, impaired memory, tachycardia.
Management: Ensure an adequate airway, oxygenation, and ventilation. Monitor cardiac functions. General supportive and symptomatic measures are also recommended. Do not induce emesis. Gastric lavage may be used if done soon after ingestion, or in symptomatic patients. Administer activated charcoal. No specific antidotes are known.

Storage Conditions
Store at 15-30° C . Protect from light and moisture.