Indications

• Anorexia/Weight Loss (see Anorexia)
  • Mirtazapine Has Appetite-Stimulant Properties
• Antipsychotic-Induced Akathisia (see Akathisia)
  • Investigational Use
• Anxiety/Social Anxiety Disorder/Panic Disorder (see Anxiety)
  • Mirtazapine Has Anxiolytic Properties
• Depression (see Depression)
  • Tetracyclic Antidepressant
• Drug Addiction
  • Investigational Use
• Headache/Migraine (see Migraines)
• Insomnia (see Insomnia)
• Nausea/Vomiting (see Nausea and Vomiting): mirtazapine has anti-emetic properties
• Obsessive-Compulsive Disorder (OCD) (see Obsessive-Compulsive Disorder)
• Obstructive Sleep Apnea (OSA) (see Obstructive Sleep Apnea)
  • Investigational Use
• Parkinson’s Disease Psychosis (see Parkinson’s Disease)
  • Investigational Use
• Post-Traumatic Stress Disorder (PTSD) (see Post-Traumatic Stress Disorder)
• Pruritus (see Pruritus)

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Pharmacology

• Selective Antagonism at α2-Adrenergic Receptor (see α-Adrenergic Receptor Antagonists)
  • Increases Norepinephrine Release
  • Increased Serotonin Release -> acts as a functional “indirect agonist” at the serotonin 5-HT1A receptor
    • Increased serotonin 5-HT1A receptor activation is believed to be major mediator of mirtazapine and most antidepressant drugs
    • However, mirtazapine does not have any significant affinity for the serotonin, norepinephrine, or dopamine transporters -> lacks any significant effects as a reuptake inhibitor of these neurotransmitters
    • Also, mirtazapine does not have any significant inhibitory effects on monoamine oxidase (MAO)
• Antagonism at Serotonin 5-HT2 Subfamily Receptors and Inverse Agonism at 5-HT2C Serotonin Receptor: likely responsible for at least part of mirtazapine’s antidepressant effect
• Antagonism at Serotonin 5-HT3 Receptor (see Serotonin 5-HT3 Receptor Antagonists)
  • Responsible for Anti-Emetic Effects (and for its Use in Nausea/Vomiting, Diarrhea, and Irritable Bowel Syndrome)
  • Effective in the Treatment of Drug Addiction
• Very Potent Inverse Agonism at Histamine H1 Receptor: results in sedative effects
• Anti-Nociceptive Properties: similar to other antidepressants

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Administration

Oral (PO)

• Dose: xxx

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Adverse Effects

Endocrinologic Adverse Effects

• Hypertriglyceridemia (>500 mg/dL) (see Hypertriglyceridemia)
  • Frequency: occurs in 6% of cases = common
• Weight Gain (at least 7% weight gain) (see Weight Gain)
  • Frequency: occurs in 49% of pediatric cases = very common

Gastrointestinal Adverse Effects

• Constipation
  • Frequency: occurs in 13% of cases = very common
• Dry Mouth
  • Frequency: occurs in 25% of cases = very common
• Increased Appetite
  • Frequency: occurs in 17% of cases = very common
• Increased ALT
  • Frequency: occurs in 2% of cases = common

Hematologic Adverse Effects

• Aplastic Anemia (see Aplastic Anemia)
  • Frequency: rare
• Eosinophilia (see Peripheral Eosinophilia)
  • Frequency: rare
• Leukopenia/Neutropenia (see Leukopenia and Neutropenia)
  • Frequency: rare
• Pancytopenia (see Pancytopenia)
  • Frequency: rare
• Thrombocytopenia (see Thrombocytopenia)
  • Frequency: rare

Neurologic Adverse Effects

• Asthenia
  • Frequency: occurs in 8% of cases = common
• Disturbance in Thinking
  • Frequency: occurs in 3% of cases = common
• Dizziness (see Dizziness)
  • Frequency: occurs in 7% of cases = common
• Headache (see Headache)
  • Frequency: uncommon
• Somnolence
  • Frequency: occurs in 54% of cases = very common

Toxicologic Adverse Effects

• Serotonin Syndrome (see Serotonin Syndrome)

Other Adverse Effects

• Bullous Dermatitis (see Vesicular-Bullous Skin Lesions)
  • Frequency: rare
• Lower Extremity Edema (see Peripheral Edema)
  • Frequency: common
• Serotonin Syndrome (see Serotonin Syndrome)

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References

• xxx