Reviewed on 7/28/2021

What Is Mirtazapine and How Does It Work?

Mirtazapine is indicated for the treatment of a major depressive disorder.

Mirtazapine is available under the following different brand names: Remeron, and Remeron SolTab.

What Are Dosages of Mirtazapine?

Dosages of Mirtazapine:

Adult and Pediatric Dosage Forms & Strengths


  • 7.5 mg
  • 15 mg
  • 30 mg
  • 45 mg

Disintegrating tablet

  • 15 mg
  • 30 mg
  • 45 mg

Dosage Considerations – Should be Given as Follows:


  • Adult: 15 mg orally at bedtime; may increase no more frequently than every 1-2 weeks; not to exceed 45 mg at bedtime
  • Geriatric: 7.5 mg/day orally at bedtime; increase by 7.5-15 mg/day no more frequently than every 1-2 weeks; not to exceed 45 mg/day

Alzheimer Dementia-related Depression, Geriatric

  • 7.5 mg/day orally at bedtime; increase by 7.5-15 mg/day no more frequently than every 1-2 weeks; not to exceed 60 mg/day

Post-traumatic Stress Disorder (Off-label)

  • 15 mg orally at bedtime; may increase no more frequently than every 1-2 weeks; not to exceed 60 mg at bedtime

Hot Flashes (Off-label)

  • 7.5-60 mg orally once/day

Insomnia (Off-label)

  • 15-45 mg orally at bedtime

Dosing Modifications

  • Renal impairment (CrCl less than 39 mL/min): Clearance is reduced; monitor closely
  • Hepatic impairment: Clearance is reduced; monitor closely

Dosing Considerations

  • Pediatric: Safety and efficacy not established
  • Geriatric: The elderly have reduced clearance of mirtazapine and, as a result, may have increased plasma levels of the drug. Use with caution


Depression is a(n) __________ . See Answer

What Are Side Effects Associated with Using Mirtazapine?

Common side effects of mirtazapine include:

  • Drowsiness
  • Weight gain
  • Dry mouth
  • Increased appetite
  • Constipation
  • Lack of energy
  • Weakness
  • Dizziness
  • Serum triglycerides increased
  • Dream disorders
  • Disturbance in thinking
  • ALT increased
  • Swelling of extremities
  • Muscle pain
  • Confusion
  • Urinary frequency
  • Tremor
  • Back pain
  • Shortness of breath

Less common side effects of mirtazapine include:

Other side effects of mirtazapine include:

Postmarketing side effects of mirtazapine reported include:

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

What Other Drugs Interact with Mirtazapine?

If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider or pharmacist first.

Severe Interactions of mirtazapine include:

Serious Interactions of mirtazapine include:

Mirtazapine has moderate interactions with at least 243 different drugs.

Mild Interactions of mirtazapine include:

This information does not contain all possible interactions or adverse effects. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns or for more information about this medicine.


Learn to Spot Depression: Symptoms, Warning Signs, Medication See Slideshow

What Are Warnings and Precautions for Mirtazapine?


  • In short-term studies, antidepressants increased the risk of suicidal thinking and behavior in children, adolescents, and young adults (younger than 24 years) taking antidepressants for major depressive disorders and other psychiatric illnesses
  • This increase was not seen in patients older than 24 years
  • A slight decrease in suicidal thinking was seen in adults older than 65 years
  • In children and young adults, risks must be weighed against the benefits of taking antidepressants
  • Patients should be monitored closely for changes in behavior, clinical worsening, and suicidal tendencies
  • This should be done during the initial 1-2 months of therapy and dosage adjustments; the patient's family should communicate any abrupt changes in behavior to the healthcare provider
  • Worsening behavior and suicidal tendencies that are not part of the presenting symptoms may require discontinuation of therapy
  • This drug is not approved for use in pediatric patients
  • This medication contains mirtazapine
  • Do not take Remeron or Remeron SolTab if you are allergic to mirtazapine or any ingredients contained in this drug
  • Keep out of reach of children
  • In case of overdose, get medical help or contact a Poison Control Center immediately


  • Hypersensitivity
  • Within 14 days of administration of MAOIs (serotonin syndrome)
  • Patients receiving linezolid or methylene blue IV

Effects of Drug Abuse

  • No information available

Short-Term Effects

  • See "What Are Side Effects Associated with Using Mirtazapine?"

Long-Term Effects

  • See "What Are Side Effects Associated with Using Mirtazapine?"


  • Start slowly in hepatic or renal dysfunction and in the elderly
  • Clinical worsening and suicidal ideation may occur despite medication
  • Rare reports of serotonin syndrome, particularly when co-administered with other serotonergic drugs
  • Abrupt discontinuation may cause dizziness, abnormal dreams, sensory disturbances (including paresthesia and electric shock sensations), agitation, anxiety, fatigue, confusion, headache, tremor, nausea, vomiting, and sweating
  • Bone fractures reported with therapy; consider possibility of fragility fracture if patient complains of bone pain, swelling, or bruising
  • Akathisia and psychomotor restlessness associated with antidepressant use
  • Rare reports of hyponatremia; caution in elderly or if co-administered with other drugs known to cause hyponatremia
  • Risk for potentially life-threatening serotonin syndrome and neuroleptic malignant syndrome-like reactions has been reported with SSRIs, SNRIs, MAOIs, and other serotonergic drugs used as monotherapy, but particularly with concomitant use of the following agents: serotonergic drugs (including triptans), drugs that impair metabolism of serotonin (including MAOIs), antipsychotics, dopamine antagonists, and non-psychiatric MAOIs (e.g., linezolid, IV methylene blue)
  • May cause anticholinergic effects; use with caution in patients with xerostomia, BPH, paralytic ileus, or decreased intestinal motility
  • Risk of mydriasis; may trigger angle closure attack in patients with angle closure glaucoma with anatomically narrow angles without a patent iridectomy
  • May increase serum triglycerides and cholesterol levels
  • May cause orthostatic hypotension (low risk); use with caution in patients at risk
  • Sexual dysfunction may occur (incidence lower compared to SSRIs)
  • May worsen psychosis in some patients or precipitate mania or hypomania in patients with bipolar disorder
  • Use with caution in patients with history of seizures, head trauma, alcoholism, brain damage, and patients on medications that may lower seizure threshold
  • QTc prolongation, ventricular fibrillation, and torsade de pointes rarely reported; use caution in patients with history of QTc prolongation, receiving QTc prolonging agents concomitantly, or with cardiovascular disease
  • Discontinue therapy if neutropenia/agrunolocytosis occur
  • May cause CNS depression, which may impair abilities to perform hazardous tasks that require mental alertness
  • May increase serum cholesterol and triglyceride levels
  • May increase appetite and cause weight gain

Pregnancy and Lactation

  • Use mirtazapine with caution during pregnancy if benefits outweigh risks
  • Animal studies show risk and human studies are not available or neither animal nor human studies done
Medscape. Mirtazapine.
DailyMed. Mirtazapine.

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