an overview of atypical anti depressants
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Atypical Anti-depressants
Brajesh LahriFinal Professional MBBS Student
All India Institute of Medical Sciences (AIIMS), Bhopal
By the end of discussion you should be able to…• Classify anti-depressants
• Enlist atypical anti-depressants
• Know about the mechanism of action of atypical anti-depressants
• Know about the indications of atypical anti-depressants
• Know about the side effects of atypical anti-depressants
Introduction• Major Depression and Mania are two extremes of affective disorders,
referring to pathological change in mood state.• Depression is characterized by symptoms like sad mood, loss of
interest and pleasure in activities, low energy, feeling of guilt, agitation, change in appetite, sleep disturbances, suicidal thoughts etc.• Anti-Depressants are drugs which help to elevate mood in depressive
illness.
Pathophysiology of depression• Many theories are given, most accepted is Monoamine Hypothesis.
• It states that deficiencies in various monoamine neurotransmitters are responsible for corresponding symptoms of depression.
• According to the monoamine hypothesis, Serotonin, norepinephrine, and dopamine are the neuro-transmitters associated in pathophysiology of depression.
**(Serotonin, Nor-epinephrine and Dopamine levels are decreased in depression)
Classification of Anti-Depressants
Anti-
Depr
essa
nts Reversible Inhibitors of
MAO-A (RIMAs)Examples: Moclobemide,
Clorgyline
Tri-Cyclic Anti-depressants (TCAs)
Examples: Imipramine, Amitriptyline, Clomipramine
Selective Serotonin Reuptake Inhibitors (SSRIs)
Examples: Fluoxetine, Paroxetine, Sertaline,
Citalopram, Dapoxetine
Serotonin and Nor-adrenaline Reuptake
Inhibitors (SNRIs)
Examples: Venlafaxine, Duloxetine
Atypical Anti-depressantsExamples: Trazodone,
Mirtazapine, Bupropion, Tianeptine
Atypical Anti-depressants
•Mirtazapine
• Trazodone
• Bupropion
• Tianeptine
• Agomelatine
Mirtazapine• Mechanism of Action Blocks α-1 receptors (present on NA neurons) and Hetero receptors (5HT-2) (present on 5-HT neurons), enhancing both NA and 5HT release.** Also, Mirtazapine is said to have some affinity for α-2 receptors, which is claimed to be related to their therapeutic efficacy, but this point is questionable.**(It is also a H1 blocker and quite sedative)• Adverse Effects- Increased appetite- Weight gain- Agranulocytosis (Rare)
Indications : Depression, OCD, Panic disorder, PTSD, SAD
Trazodone• Mechanism of Action Prominent α-1 adrenergic and weak 5-HT2A antagonistic action. Also acts by blocking uptake of 5HT.• Adverse Effects- Excessive Sedation-Inappropriate, prolonged and painful penile erection (Priapism)- Postural Hypotension (Due to α1 adrenergic blockade)
Indications : Generalized anxiety disorders (GAD), Panic Disorder, Eating Disorders
Bupropion• Mechanism of Action Inhibits re-uptake of Dopamine and Nor-Adrenaline. In addition may also increase the release of NA and DA.**(It has excitant rather than sedative activity)
• Adverse Effects -Insomnia and agitation- Decreases Seizure threshold
Indications : Depression, Eating Disorder, Cannabis dependence, Cocaine dependence, Nicotine dependence
Agomelatine• Mechanism of action: It acts as melatonin receptor agonist at MT1 and MT2 receptors. It also acts as a weak antagonist at 5-HT2c receptors • Adverse Effects : - Nausea and Dizziness - Increase in liver enzyme levels Indications : Depression,
resynchronization of disturbed circadian rhythm
Tianeptine• Mechanism of Action : It increases serotonin/5-HT uptake in the brain (in contrast with most antidepressant agents) and reduces stress-induced atrophy of neuronal dendrites.
• Adverse Effects: - Nausea, Constipation, Abdominal Pain- Dizziness, Headache- Hepatoxicity (Rare)
Indications : Useful in anxio-depressive states ,as well as in endogenous depression
Serotonin and Nor-Adrenaline reuptake inhibitors (SNRIs)• Venlafaxine• DuloxetineMechanism of Action : Inhibit uptake of both Nor-adrenaline and Serotonin, but do not interact with cholinergic, adrenergic or histaminergic receptors.Adverse Effects :- Dizziness ,Insomnia- Rise in BP (More common with Venlafaxine )- Associated with increased risk of Cardiac arrhythmias(Clinical significance is still unclear)
Indications: -Depression (Both) -Neuropathic pain (Duloxetine)
Reversible Inhibitors of MAO-A (RIMAs)• Moclobemide• ClorgylineMechanism of Action:Inhibit MAO-A enzyme which deaminates 5-HT and NA.Adverse Effects : -Nausea - Dizziness, Insomnia - Liver damage (Rare)
Indications: Depression and Social Phobia
References• Clinical Pharmacology-11th Edition - Bennett, Brown and Sharma• Goodman-Gilman’s -The Pharmacologic basis of Therapeutics- 12th
Edition – Brunton, Chabner, Knollmann• Essential Medical Pharmacology-7th Edition - K.D. Tripathi• Essential Evidence based Psychopharmacology- 2nd Edition- Stein ,
Lerer and Stahl
Thank You
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