Antidepressant Drugs and the Psychopharmacology of Depression

Question 1

What are the 2 types of depression?

How is depression diagnosed?

What other comorbidities is depression commonly found with?

What are the 3 common Monoamines linked with depression?

Which drug class is recommended by NICE for first-line treatment of depression?

Answer 1

• 1. Unipolar Depression; Mood swings in one direction (depression)
     
     2. Bipolar Depression; Fluctuation between Depression and Mania
        o Type 1 - More Manic episodes with/without depression
        o Type 2 - Hypomania with frequent major depressive episodes
• Shows at least 5 symptoms during a 2-week period and represents change from previous functioning
• Terminal/Chronic/Neurological disease, Drug abuse, Anxiety
• Serotonin, NA, Dopamine
• SSRIs

Question 2

Monoamine Oxidase Inhibitors (MAOI):
When is it used?

What do they do?

What’s the function of Reversible MAOIs (RIMA)?

What is the Cheese Effect? What are the symptoms?

Why are RIMAs safe?

What are the side-effects of MAOIs?

Answer 2

• Only used in Severe depression when other ADs don’t work
• Inhibit breakdown of Monoamines to ↑Monoamine in synaptic cleft
• To reduce the Cheese Effect; e.g. Moclobemide
• Dietary amines e.g. Tyramine (in cheese and wine) acts as an indirect sympathomimetic and ↑NA release; with MAOI, NA accumulates a lot = Headache, Intracranial Haemorrhage = HYPERTENSIVE CRISIS
• Accumulation of NA displaces the RIMA, allowing for NA breakdown
• Postural Hypotension, Excessive CNS stimulation (Tremors, Insomnia), ↑Appetite (Weight gain), Antimuscarinic effects (Constipation, Dry mouth, Blurred vision, Micturition difficulty)

Question 3

Tricyclic Antidepressants (TCA):
What do they do? Give an example

What is the effect in the short and long term?

What are the side-effects?

How do TCAs interact with other drugs?

Who shouldn’t be given these drugs not be used?

Answer 3

• Block Serotonin and NA reuptake channels; e.g. Amitriptyline
• Initial ↑[NA] and [Serotonin] in synaptic cleft, Chronic treatment causes the downregulation of Serotonin and NA receptors
• Anticholinergic and Antimuscarinic effects, Weight gain, Postural Hypotension, Confusion, Arrhythmia, Low therapeutic effects
• Metabolism of TCAs is inhibited by certain drugs, TCAs potentiate effects of alcohol and anaesthetics
• Not to be used in elderly, dementia, heart disease patients

Question 4

Selective Serotonin Reuptake Inhibitors (SSRIs):
What do they do? Give an example

What is the effect if taken long term?

Why are SSRIs safer in overdose?

What are the side-effects?

Answer 4

• Selectively block Serotonin (5-HT) reuptakers; e.g. Citalopram, Fluoxetine
• Chronic action = Downregulation of 5-HT receptors, ↑[Serotonin]
• Has less anticholinergic effects; better compliance
• • 5-HT2; Insomnia, Sexual dysfunction
  • 5-HT3; Nausea, Gi problems, Headache