TINY GELDENHUYS
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Blog #12

18 May 2021, 13:52 Publicly Viewable

BLOG #12

1. Draw up a classification of the drugs that are used as antidepressants.

  1. TCA’s 

Tertiary: 

  • Amitriptyline 
  • Imipramine 
  • Trimipramine 
  • Chlorimipramine 

Secondary:

  • Nortriptyline 
  • Desimipramine  
  • Tetracyclic drugs
  1. MAO Inhibitors:
  • Tranylcypromine 
  • Phenelzine 
  • Selegiline 

MAO-A: 

  • Noradrenaline 
  • Serotonin 

MAO-B:

  • Dopamine 
  • Tyramine 
  1. SSRI
  • Fluoxetine 
  • Paroxetine 
  • Fluvoxamine 
  1. SNRI
  • Duloxetine 
  • Venlafaxine 
  • Levomilancipran 
  1. NARI
  • Reboxetine 
  1. Tetracyclic and unicyclic AD
  • Bupropion
  • Mirtazapine 
  • Vilazodone 
  • Maprotiline 
  1. 5- HT2 R Modulators
  • Trazodone]
  • Vortioxetine 
  1. Circadian rhythm regulators
  • Agomelatine 

2. What do the existing drugs all have in common regarding their mechanisms of action?

Most of the drugs increase [NA] and [5-HT] at the central synapses. 

3. How long does it take for the antidepressive effects of these drugs to appear? What is the reason for this?

14-21 days- the onset of action 

3-5 weeks- clinical response

Multipotent actions on numerous monoaminergic receptors due to a non-specific increase in 5-Ht or NA. 

4. How do the TADs and the selective serotonin reuptake inhibitors (SSRI’s) differ in respect of: 

 

TAD’s 

SSRI’s 

Efficacy 
  • Well absorbed 
  • Long half-lives 
  • Extensively metabolized by the liver. 
  • Short half-lives

Side effects 

Antimuscarinic: 

  • Dry mouth 
  • Constipation 
  • Blurred vision 
  • Urinary retention 

Alpha-lytic:

  • Erectile dysfunction 
  • Orthostatic hypotension 
  • Blurred vision 
  • Dry mouth 
  • Dizziness 
  • Constipation 
  • Weight loss

Safety

Narrow therapeutic window at relatively low doses, therefore drug overdose potential. 

Overdose potential. 

Venlafaxine toxicity: 

  • Anticholinergic effects 
  • Sedation 
  • Hypotension 
  • Anxiety 
  • Nausea 
  • Sweat
  • Dizziness
  • Sexual disturbance 

5. What is the action of mirtazapine?

Is a NaSSA: NA and specific serotonin AD. Blockade of a2, 5-HT 2A & 5- HT3. Also blocks H1, a1 and indirect stimulation of 5-HT 1A.

6. What is the action of venlafaxine?

Blocks both 5-HT and NA reuptake more potent for 5-HT than for NA.

7. What is the action of agomelatine?

Antagonist: 5-HT 2c

Agonist: Melatonergic receptors- MT1 and MT 2