Antidepressants

Question 1

Lithium

Answer 1

Anti-mania drug - clinically used to treat bipolar disorder

Mood stabiliser: prevents oscillations of manic depressive disorder and helps with depressive phases.
Anti-aggressive effects

Mechanism of Action (not fully understood: Increases serotonin, decreases NA, decreases GSK3 (glycogen synthase kinase) and a disruption in ion balance (can cause adverse effects) &
upregulates complex 2 and 3 of ETC (thought that this may be dysregulated in bpd).

Very safe drug (if given within its therapeutic window), high toxicity above therapeutic level: Seizures
ADHR damage in kidney → polyuria, polydipsia and hypothyroidism.

Question 2

Imipramine

Answer 2

Tricylclic antidepressant - non-selective amine uptake inhibitor - Blocks SERT & NET.

Also blocks alpha-adrenergic (orthostatic hypotension), H1 receptors (sedation) and muscarinic receptors (anticholinergic). These blockades thought to be the reason for adverse effects

Mood elevator with some anxiolytic effects
Weight gain (good for anorexia) - can  be excessive.
Effective for chronic pain due to its effect on Na+ channels.

Adverse Effects: Tremor, antimuscarinic, sedation, hypotension, cardiac depression and seizures because of Na+ imbalance.

No longer used widely due to adverse effects
Delayed onset: ~2 weeks; risky for at risk (suicide) people

Question 3

Flouxetine

Answer 3

SSRI (selective serotonin reuptake inhibitors) - act on SERT therefore more serotonin available to bind the receptors

Side effects (better than older treatments:
Non-sedative so may cause acute anxiety and insomnia as well as mania in bipolar patients, precipitate anorexia,
sexual dysfunction, hyponatremia, suicidal thoughts in the young up to the age of 25.

Question 4

Reboxetine

Answer 4

SNRI (selective noradrenaline reuptake inhibitor) - blocks SERT and NET from reuptaking 5HT and NA. Efficacy similar to TCAs overall but may work better in some patients over others.

Do not affect 5HT receptors at therapeutic levels

Side effects: dizziness, insomnia, anticholinergic effects - SE profile similar to SSRIs.

Question 5

Bupropion

Answer 5

Atypical antidepressant - NDRI (noradrenaline dopamine reuptake inhibitor) - causes a very weak block of various receptors, specifically it is a weak dopamine, 5HT and NA uptake inhibitor.

Side effects: dose dependant risk of seizures, a weird side effect is that it decreases the craving for nicotine in smokers as it blocks the 4/2ACh receptor.

Question 6

Venlaxafine

Answer 6

SSNRI (selective serotonin noradrenaline reuptake inhibitor).

Generally have better side effect profiles than SSRIs and SNRIs and have similar efficacy, safe in overdose

Question 7

Mirtazapine

Answer 7

Tetracyclic antidepressant

Alpha2 and 5HT2 receptor antagonist

NB: 5HT2a antagonism causes antidepressive effects due to redistribution of the serotonin to other receptors. 5HT2a stimulation is thought to be a cause of depression.

Question 8

Trazodone

Answer 8

Atypical antidepressant with SSRI activity
5HT2a receptor antagonist

NB: 5HT2 antagonism causes antidepressive effects due to redistribution of the serotonin to other receptors. 5HT2a stimulation is thought to be a cause of depression.

Question 9

Agomelatine

Answer 9

5HT2a antagonist and melatonin agonist

NB: 5HT2a antagonism causes antidepressive effects due to redistribution of the serotonin to other receptor. 5HT2a stimulation is thought to be a cause of depression.s

Question 10

Vilazodone

Answer 10

Atypical antidepressant with SSRI activity (blocks SERT)

5HT1a partial agonist (1a receptors are pre & postsynaptic thus we get feedback inhibition)