Introduction and mechanism of action

By : Ola S. Eldardiry

Anti depressants

Psychiatric medications given to patients with depressive disorders to alleviate symptoms.

Types:

1. Monoamine oxidase inhibitors (MAOIs)

2. Noradrenaline and specific serotoninergic antidepressants (NASSAs)

3. Serotonin and noradrenaline reuptake inhibitors (SNRIs)

4. Selective serotonin reuptake inhibitors (SSRIs)

5. Tricyclics (TCAs)

Onset: delayed up to few weeks.

Duration of treatment: few months or several years

Serious problem = lack of compliance

Uses

• Agitation• Obsessive compulsive disorders (OCD)• Childhood enuresis (bedwetting)• Depression • Generalized anxiety disorder• Major depressive disorder• Manic-depressive disorders• Posttraumatic stress disorder (PTSD)• Social anxiety disorder

Primary (approved)

• Binge eating disorder• Bulimia nervosa• Chronic urticaria (hives)• Fibromyalgia• Osteoarthritis pain• Hot flashes• Diabetic peripheral

neuropathic pain• Neuropathic pain• Hyperhidrosis (drug-

induced)• Premenstrual symptoms • Tourette syndrome

• Ruritus (itching) • Migraines• Snoring

“Off-label” – unapproved indication

Mechanism of actionMonoamine Oxidase Inhibitors (MAOIs)

Tricyclic Antidepressants (TCAs)

Selective Serotonin Reuptake Inhibitors (SSRIs)

Serotonin/ Norepinephrine/ Dopamine Reuptake Inhibition (SNRI) (Venlafaxine)

On comparison with SSRI:• 5-HT2 receptors are blocked• Don’t cause some side effects such as:

• Short-term increase in anxiety or insomnia• Akathisia• Sexual dysfunction

Serotonin-2 Receptor Antagonism with Serotonin Reuptake Blockade (Nefazodone, Trazodone)

Norepinephrine and Dopamine Reuptake Inhibition (Bupropion)

α-2 Antagonism plus Serotonin-2 and Serotonin-3 Antagonism (Mirtazapine)

Noradrenalin Specific Reuptake Inhibitor (NRI) (Reboxetine)

Serotonin Reuptake Enhancer (Tianeptine)

• Tricyclic compound of diabenzothiazepine type

• Increases presynaptic uptake of serotonin after single + repeated administration

• Not linked to any effects on 5-HT post-synaptic systems

• No affinity for:o α1 adrenergico H1 antihistaminico Muscarinic receptors

• Similar to TCAs but with faster onset

• Not stimulating nor sedative• No anticholinergic effect• No cardiovascular effect

Thank you