Mirtazapine
Indications
Mirtazapine is used for:
Depression, Major depressive disorder
Adult Dose
Oral
Depression
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.
Elderly
Depression
7.5 mg/day PO qHS; increase by 7.5-15 mg/day no more frequently than q1-2Weeks; not to exceed 45 mg/day
Alzheimer Dementia-related Depression
7.5 mg/day PO qHS; increase by 7.5-15 mg/day no more frequently than q1-2Weeks; not to exceed 60 mg/day
Hepatic impairment: Clearance is reduced; monitor closely
Child Dose
Safety and efficacy not established
Renal Dose
Renal impairment (CrCl <39 mL/min): Clearance is reduced; monitor closely
Administration
May be taken with or without food.
Contra Indications
Mirtazapine Tablets are contraindicated in patients with a known hypersensitivity to mirtazapine or to any of the excipients.
Precautions
Epilepsy or history of seizures; avoid completely in unstable cases. 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. Micturition disturbances, angle-closure glaucoma, raised intraocular pressure. Monitor patient for signs of bone marrow depression. Monitor patient for suicidal tendency. Avoid abrupt withdrawal. May impair ability to drive or operate machinery. Pregnancy and lactation. Elderly.
Lactation: Avoid
Pregnancy-Lactation
Pregnancy
There are no adequate and well-controlled studies in pregnant women
Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed
Animal studies
Reproduction studies in pregnant rats and rabbits at doses up to 100 mg/kg and 40 mg/kg, respectively (20 and 17 times the maximum recommended human dose [MRHD] on an mg/m2 basis, respectively), have revealed no evidence of teratogenic effects
However, in rats, there was an increase in postimplantation losses in dams treated with mirtazapine
Lactation
May be excreted in breast milk; caution advised
Interactions
Potentiation of 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. Increased bioavailability with cimetidine.
Potentially Fatal: Do not use with or within 2 wk of stopping an MAOI; at least 1 wk should elapse between discontinuing mirtazapine and initiating any drug which may provoke a serious reaction (e.g. phenelzine).
Adverse Effects
Side effects of Mirtazapine :
>10%
Somnolence (54%), Weight gain (>7% increase in <49% of pediatric patients), Xerostomia (25%), Increased appetite (17%), Constipation (13%)
1-10%
Asthenia (8%), lWeakness (8%), Weight gain (>7% increase in 8% of adults), Dizziness (7%), Serum TGs increased (6%), Dream disorder (4%), Disturbance in thinking (3%), ALT increased (2%), Peripheral edema (2%), Myalgia (2%), Confusion (2%), Urinary frequency (2%), Tremor (2%), Back pain (2%), Dyspnea (1%)
<1%
Mania (0.2%), Grand mal seizure (less than 0.1%)
Frequency Not Defined
Depression exacerbation, Status epilepticus, Suicidal thoughts, suicide (rare), Agranulocytosis, Neutropenia
Mechanism of Action
Mirtazapine, a piperazinoazepine tetracyclic antidepressant, enhances noradrenergic and serotonergic activity through blockade of central presynaptic adrenergic alpha 2-receptors.