- Elevates mood by raising the level of norepinephrine and serotonin in the brain
- Blocks the effect of histamine
Tablet: 7.5 mg, 15 mg, 30 mg and 45 mg
a. Start at 15 mg OD at hs
b. Doses may be increased every 1-2 weeks up to a maximum dose of 45 mg daily
Mirtazapine adds to the sedating effects:
Following medications increase the blood level of Mirtazapine:
- Fluvoxamine (Luvox)
- Ketoconazole (Nizoral)
- Cimetidine (Tagamet)
Following medications reduce the blood level of Mirtazapine by increasing the liver metabolism:
- Carbamazepine (Tegretol)
- Phenytoin (Dilantin)
If taken with MAOi causes:
- High fever
- an interval of 14 days is recommended between stopping MAOi and starting mirtazapine, and vice versa.
Avoid taking with SSRIs and other drugs that increase serotonin activity in the brain.
- Sumatriptan (Imitrex)
- Linezolid (Zyvox)
- Fluoxetine (Prozac)
- Venlafaxine (Effexor)
- Lithium (Eskalith, Lithobid)
- Tramadol (Ultram)
- John’s wort
- Dry mouth
- Weight gain
- Increased appetite
- High cholesterol & triglycerides
- Abnormal dreams.
- Orthostatic hypotension
- Manic episodes
- Increase the risk of suicide in children and adolescents and adults
- Worsening of depression or suicidal thoughts (closely observe for signs of worsening depression, suicidal thinking or changes in behavior)
- Mirtazapine and its active metabolite are found in breast milk, with higher levels in the hindmilk than foremilk. Adverse events have not been observed in nursing infants. The manufacturer recommends that caution be used if administered to a breast-feeding woman.
- Antidepressants increase the risk of suicidal thinking and behavior in children, adolescents, and young adults (18-24 years of age) with major depressive disorder (MDD) and other psychiatric disorders; consider risk prior to prescribing.
- Prescriptions should be written for the smallest quantity consistent with good patient care.
- You might experience any or most of the following changes while taking antidepressants: anxiety, agitation, panic attacks, insomnia, irritability, hostility, impulsivity, akathisia, hypomania, and mania. You should notify your healthcare provider if any of these symptoms or worsening depression or psychosis occur.
- Mirtazapine may cause anticholinergic effects such as constipation, xerostomia, blurred vision, urinary retention. However, the degree of anticholinergic blockade produced by Mirtazapine is low relative to other antidepressants.
- Mirtazapine should be used with caution in patients with decreased gastrointestinal motility, paralytic ileus, urinary retention, BPH, xerostomia, or visual problems.
- Mirtazapine may cause neutropenia/agranulocytosis. Discontinue immediately if signs and symptoms of these conditions occur.
- Mirtazapine may cause orthostatic hypotension. Use with caution in patients at risk of this effect or in those who would not tolerate transient hypotensive episodes such as CVA, cardiovascular disease, hypovolemia, or concurrent medication use which may predispose to hypotension/bradycardia.
- May increase appetite and stimulate weight gain. Weight gain of >7% of body weight reported in 7.5% of patients treated with mirtazapine compared to 0% for placebo.
- Use with caution in patients with hepatic impairment. Clinically significant transaminase elevations have been observed.
- Potential for severe reaction when used with MAO inhibitors; autonomic instability, coma, death, delirium, diaphoresis, hyperthermia, mental status changes/agitation, muscular rigidity, myoclonus, neuroleptic malignant syndrome features, and seizures may occur.
- Bandelow B, Zohar J, Hollander E, et al, “World Federation of Societies of Biological Psychiatry (WFSBP) Guidelines for the Pharmacological Treatment of Anxiety, Obsessive-Compulsive and Post-Traumatic Stress Disorders — First Revision,” World J Biol Psychiatry, 2008, 9(4): 248-312. Available at http://www.wfsbp.org/fileadmin/pdf/guides/Guidelines_Anxiety_revision.pdf
- Benedek DM, Friedman MJ, Zatzick D, et al, “Guideline Watch (March 2009): Practice Guideline for the Treatment of Patients With Acute Stress Disorder and Posttraumatic Stress Disorder.” Available at http://www.psychiatryonline.com/pracGuide/loadGuidelinePdf.aspx?file=AcuteStressDisorder-PTSD_GuidelineWatch
- “Mirtazapine – A New Antidepressant,” Med Lett Drugs Ther, 1996, 38(990):113-4.
- Pass SE and Simpson RW, “Discontinuation and Reinstitution of Medications During the Perioperative Period,” Am J Health Syst Pharm, 2004, 61(9):899-912.
- Rabins PV, Blacker D, Rovner BW, et al, “Practice Guidelines for the Treatment of Patients With Alzheimer’s Disease and Other Dementias,” October, 2007. Available at http://www.psych.org/psych_pract/treatg/pg/prac_guide.cfm
- Stimmel GL, Dopheide JA, and Stahl SM, “Mirtazapine: An Antidepressant With Noradrenergic and Specific Serotonergic Effects,” Pharmacotherapy, 1997, 17(1):10-21.