Antidepressants

Objectives:

•Basis for the use of the various types of anti-depressants

•Mechanisms by which these drugs act and their potential adverse effects

•Relevant pharmacokinetic aspects to the therapeutic uses of these drugs

​Different depressive symptoms reflect dysfunction in different neurotransmitter systems, which is why antidepressants with different mechanisms produce different clinical effects.

Autoreceptors & heteroreceptors

• Autoreceptors & heteroreceptors in CNS functions as negative feedback mechanisms

• Response to AD drugs (eg. SSRIs) by 5-HT1A autoreceptors stimulation: initial reduce 5-HT release, subsequently desensitize by receptor internalisation & restores/enhanced 5-HT release

• α2 autoreceptors modulate NA release

Multiple Choice

These are mechanisms of antidepressant drug actions EXCEPT

• alpha-2 autoreceptor blockade

• serotonin 5-HT1A autoreceptor blockade

• serotonin 5-HT1A agonist

• Serotonin reuptake transporter blockade

• serotonin 5-HT2C blockade

​Other examples: Citalopram, escitalopram, paroxetine

​This makes the classical triad

Open Ended

List 3 SSRI drugs

Open Ended

List the triad of serotonin syndrome

Multiple Choice

A 55-year-old lady with type 2 diabetes mellitus has been having chronic pains over her hands and feet. She described the pain as being burning in nature and is worse at night. The pain is not relieved by paracetamol or ponstan. This has made her depressed. Which of the following drugs may be used to treat this lady?

• Duloxetine

• Mirtazapine

• Bupropion

• Moclobemide

Pain can be modulated via descending pathway

ADs which act by increasing NA (and 5-HT) such as duloxetine and amitriptyline works by increasing NA in the dorsal horn​

​

​ADs and neuropathic pain

Multiple Select

Weight gain seen with mirtazapine treatment is most likely due to effects on this/these receptor(s) (can be more than 1 answer):

• 5-HT2A

• 5-HT2C

• 5-HT1A

• 5-HT3

• H1

Multiple Choice

The tyramine-reaction seen with MAOI-tyramine rich food is due to

• centrally acting tyramine effect

• tyramine effect on peripheral α and β receptors

​Add agomelatine & vortioxetine to the list!

EdPuzzle Video: Self study

https://edpuzzle.com/open/damabuf

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