1. Using your textbooks, draw up a classification of the drugs that are used as antidepressants.

Classification	Drug
Tricyclic antidepressants (TCA)	Tertiary Amine Amitriptyline Imipramine Trimipramine Chlorprimipramine Dothiepine Butriptyline Secondary Amine Nortiptyline Desimipramine Lofepramine
Monoamine oxidase inhibitors (MAOI’s)	Tranylcyclopromine: Non selective MOAI Moclobemide: Selective MOA-A inhibitor
Selective 5HT reuptake inhibitors (SSRI)	Fluoxetine Paroxetine Fluvoxamine Sertraline Citalopram Escitalopram
Serotonin and noradrenalin reuptake inhibitors (SNRI’s)	Venflaxine Duloxetine
Selective noradrenaline reuptake inhibitors (NAR’s)	Reboxetine
Tetracylcic and unicyclic AD’s	Mianserin (Tetracyclic) Mirtaxepine (Tetracyclic) Bupropion (Unicyclic)
5-HT2 Receptor modulators	Trazodone Vortioxetine
Circadian rhythym regulators	Aglomelatine

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

Multipotent actions on numerous monoamine receptors which leads to the non-specific increase of 5-HT or NA

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

The clinical response can take up to 3-5 weeks. This long period can be explained by the effects of the antidepressant drug on the neurotrphic factors. It can take two weeks or longer for the synthesis of neurotrophic factors to take place.

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

*Look up in textbook and add

	TAD’s	SSRI’s
Efficacy	Require up titration to minimum effective dosage	Can immediately start with full dosage administration
Side effects	Sedation Tremore and insomnia (Sympathomimetic effects) Visual disturbances, Dry mouth, Constipation, Urinary retention, confusion (Anti-cholinergic effects) Cardio-vascular: Orthostatic hypotention. Dysrhthmia Convulsions Metabolic-endocrine: Weigh decrease, Sexual disturbances Psychosis and can precipitate mania	Anxiety Sexual dysfunction Insomnia Headache GIT distubrances Decreases Libido Extra-pyramidial side effects Withdrawal syndrome
Safety	Acute overdose is extremely dangerous and can lead to: coma, convulsions and cardio-toxicity	Safer to use, fewer side effects

5. What is the action of mirtazapine?

Tetracyclic Antidepressant. Mirtrazepine primarily blocks a2 receptors which causes an increase in NA(autoreceptors) and 5-HT(heterorecpetors) release.

It also blcoks  5-HT2A (Anti-depressive effects)  and blocks 5-HT3 (anxiolytic and decrease nausea).

Additionally it also blocks H1 receptors which leads to sedation and weight gain, and it blocks a1 receptors which can lead to postural hypotension.

6. What is the action of venlafaxine?

Serotonin and noradrenaline reuptake inhibitor. Blocks both 5-HT and NA re-uptake, but has a higher affinity for 5-HT than NA

7. What is the action of agomelatine?

Circadian rhythm regulator. MT 1 and MT 2 agonist and 5-HT2c antagonist. MT 1 and MT 2 agonism helps in regulation of circadian rhythyms and improves sleep. 5-HT2C antagonism improves sleep through regulation of circadian rhythms and also provides antidepressant action. 5-HT2C antagonism leads to disinhibition of DA and NA release in the frontal cortex, which leads to an increase in Dopamine and NA release.

Brand, L. 2021. Anti-depressants. Study Unit 10. [PowerPoint Presentation]. Study Unit 10, FKLG 312. Potchefstroom, NWU.