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

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

• They increase noradrenaline and serotonin at central synapses.

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

• 14 to 21 days or more, the drugs have a slow onset of action.

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

Efficacy

• TADs have  a mixed and variable blockage of Norepinephrine Transporter (NET)  and Serotonin Transporter (SERT) while SSRIs have a highly selective blockage of SERT and little effect on NET.

Side effects

• TCAs -anticholinergic effects, alpha-blocking effects, sedation and weight gain

      SSRIs-Sexual dysfunction

Safety

• TCAs interact with CYP inducers and inhibitors, while SSRIs are CYP inhibitors.

What is the action of mirtazapine?

• Blockage of serotonin 2A and 3 receptors and Histamine 1 and alpha 1 receprors

What is the action of venlafaxine?

• Blocks serotonin and noradrenalin re-uptake.

What is the action of agomelatine?

• Agonist on the melatonin 1&2 receptors and antagonist on serotonin 2A receptors.