Mirtazapine (Remeron, Avanza, Axit, Mirtaz, Mirtazon, Zispin)
Indications
Anorexia/Weight Loss (see Anorexia , [[Anorexia]]): mirtazapine has appetite-stimulant properties
Antipsychotic-Induced Akathisia : investigational use
Anxiety/Panic Disorder (see Anxiety , [[Anxiety]]): mirtazapine has anxiolytic properties
Depression (see Depression , [[Depression]]): tetracyclic antidepressant
Drug Addiction : investigational use
= Headache/Migraine (see Migraine , [[Migraines]])
Insomnia
Nausea/Vomiting (see Nausea and Vomiting , [[Nausea and Vomiting]]): mirtazapine has anti-emetic properties
Obsessive-Compulsive Disorder (OCD)
Obstructive Sleep Apnea (OSA) : investigational use
Parkinson’s Disease Psychosis : investigational use
Post-Traumatic Stress Disorder (PTSD)
Pruritus
Social Anxiety Disorder
Pharmacology
Selective Antagonism at α2-Adrenergic Receptor (see α-Adrenergic Receptor Antagonists , [[α-Adrenergic Receptor Antagonists]])
Increases Norepinephrine Release
Increased Serotonin Release -> acts as a functional “indirect agonist” at the 5-HT1A receptor
Increased 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 5-HT2 Serotonin Subfamily Receptors and Inverse Agonism at 5-HT2C Serotonin Receptor : likely responsible for at least part of mirtazapine’s antidepressant effect
Antagonism at 5-HT3 Serotonin Receptor (see Serotonin 5-HT3 Receptor Antagonists , [[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 H1 Receptor : results in sedative effects
Anti-Nociceptive Properties : similar to other antidepressants
Administration
Adverse Effects
Gastrointestinal Adverse Effects
Constipation : present in 13% of cases = very common
Dry Mouth : present in 25% of cases = very common
Increased Appetite : present in 17% of cases = very common
Increased ALT : present in 2% of cases = common
Weight Gain (at least 7% weight gain) : present in 49% of pediatric cases = very common
Neurologic Adverse Effects
Asthenia : present in 8% of cases = common
Disturbance in Thinking : present in 3% of cases = common
Dizziness : present in 7% of cases = common
Headache : uncommon
Somnolence : present in 54% of cases = very common
Other Adverse Effects
Blood Dyscrasias (agranulocytosis, anaemia, aplastic anaemia, eosinophilia, granulocytopenia, neutropenia, pancytopenia, thrombocytopenia) : rare
Bullous Dermatitis : rare
Hypertroglyceridemia (>500 mg/dL): present in 6% of cases = common
Lower Extremity Edema (see Lower Extremity Edema , [[Lower Extremity Edema]]): common
Serotonin Syndrome (see Serotonin Syndrome , [[Serotonin Syndrome]])
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References
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