One liners about antidepressants

Introduction:

• According to the biological theory of depression, reduction of 3 monoamines in our brain (serotonin, norepinephrine and dopamine); also known as trimonoaminergic depletion is responsible for depression
• Antidepressants works primarily by decreasing the sensitivity of the neuroreceptors of the any of the 3 monoamines specified, in a long term basis.

Family of the antidepressants:

1. Tricyclic antidepressants (TCA): Inhibits reuptake of all 3 monoamines
2. Selective serotonin reuptake inhibitor (SSRI)
3. Serotonin and norepinephrine reuptake inhibitors (SNRI)
4. Norepinephrine-dopamine reuptake inhibitor (NDRI).

Uses of TCA:

1. Clomipramine: Gold standard drug for OCD
2. Imipramine: Nocturnal enuresis (DOC: Desmopressin)
3. Amitriptyline: Tension type headache
4. Nortriptyline: Post-stroke depression.

SSRI:

• Fluvoxamine has the shortest half life among all SSRIs; so, it has the highest risk of drug discontinuation syndrome
• Fluoxetine has the longest half life among all SSRIs; so, it has no risk of drug discontinuation syndrome
• SSRIs are the DOC in following conditions:
  1. Depression
  2. Atypical depression
  3. Premenstrual dysphoric disorder
  4. Panic disorder (Chronic anxiety)
  5. Phobia
  6. OCD
  7. Post-traumatic stress disorder (PTSD)
  8. Premature ejaculation.
• MC side effect of SSRI is nausea and vomiting (due to increased amount of serotonin acting on CTZ area of brain)
• Most characteristic side effect of SSRI is delayed ejaculation; for this property, SSRIs are used in the treatment of premature ejaculation.

Miscellaneous uses of SNRI (other than depression):

• Venlafaxine: MC-ly used SNRI
• Duloxetine: Fibromyalgia, diabetic neuropathy & chronic pain syndrome
• Atomoxetine: ADHD
• Sibutramine: Marketted for treatment of obesity, withdrawn due to cardiovascular adverse events.

NDRI: Bupropion-

• Bupropion is prescribed as an aid for smoking cessation. It reduces the severity of nicotine cravings and withdrawal symptoms.

Newer agents:

• NaSSA: Mirtazapine
• SARI: Trazodone
• SSRE: Tianeptine
• SPARI: Vilazodone.

*NaSSA: Noradrenergic specific serotonergic agent, SARI: Serotonergic antagonist & reuptake inhibitor, SSRE: Selective serotonin reuptake enhancer, SPARI: Serotonin partial agonist & reuptake inhibitor.