Antidepressants

Question 1

Name the classes of antidepressants with examples

Answer 1

• mono amine oxidase inhibitors (MAOI): phenelzine
• reversible MAOI (RIMA): moclobemide
• tricyclic antidepressants: amityriptyline/clomipramine
• SSRI: fluoxetine
• SNRI: duloxetine

Question 2

Describe the mechanism of action of MAOI and its side effects

Answer 2

inhibit the activity of MAO enzymes (that breakdown norepinephrine, serotonin and dopamine)

side effects: weakness, fatigue, weight gain, headache, dizzy, impotence

Question 3

What are the dangers of MAOI?

Answer 3

• can cause dangerously high levels of serotonin when given with SSRIs/tricyclic antidepressants or morphine/tramadol
• foods high in tyramine can cause hypertensive crisis (eg. cheese)

Question 4

Describe the mechanism of action of RIMA

Answer 4

reversible inhibition of MAO type A

Question 5

Describe the mechanism of action of tricyclic antidepressants

Answer 5

• inhibit the re-uptake of norepinephrine and serotonin by blocking transporters
• increases concentration of NT in synapse which increases neurotransmission
• can increase transmission in nerve endings of pain control pathways so can be used for neuropathic pain

Question 6

What are the dangers of tricyclic antidepressants?

Answer 6

• risk of arrhythmias in CVD
• decreases intestinal mobility due to anti-muscarinic activity
• can cause bradycardia followed by tachycardia, decreased bronchial secretions, urinary retention, dry mouth and confusion
• very dangerous in overdose

Question 7

What is the mechanism of action of SSRIs?

Answer 7

• increases levels of serotonin by decreasing re-uptake
• acts on 5-HT receptors
• have low affinity for norepinephrine and dopamine

Question 8

What are the side effects of SSRIs?

Answer 8

• sexual dysfunction
• cardiac (esp citalopram in QT prolongation)
• bleeding risk (GI)
• can increase risk of suicide
• epilepsy
• insomnia
• nausea