L35 Drugs used in mental health disorders I Anti-depressants

Question 1

Mechanism, Contraindication, S/E of Serotonin selective reuptake inhibitor (SSRI)

Answer 1

Fluoxetine (Prozac) Paroxetine (with relative severe
weight gain/ sexual dysfunction)

potential inhibitors of the CYP2D6
isoenzyme,
MoA
Block reuptake of serotonin
by the presynaptic neuron, thus
maintaining high levels of 5-HT in
the synapse.

Primary action is the inhibition of
the serotonin transporter.→

Adverse effects of SSRI
Nausea , GI upset, diarrhea
Diminished sexual function and interest
Reduced coagulation Increased risk of bleeding
Favors Vasoconstriction

Question 2

Mechanism, Contraindication, S/E of Noradrenaline reuptake inhibitor

Answer 2

MoA
Atomoxetine Reboxetine
→Selectively blocks the reuptake of noradrenaline by binding to the NA transporter on the pre-synapse
→Increase NA concentration in synaptic cleft

Adverse effects
→Increase blood pressure
→→noradrenaline interacts with alpha receptors in the arteries,
→ Alter heart rate
→→interacts with beta receptors found on pacemaker cells
→ CNS activation (e.g. insomnia, anxiety, agitation)

Question 3

Mechanism, Contraindication, S/E of Serotonin-Norepinephrine Reuptake inhibitors

Answer 3

Venlafaxine Desvenlafaxine
MoA
→Binds to both the serotonin
and norepinephrine
transporters.

→Block nonepinephrine and
serotonin reuptake.

Adverse effects
Same adverse effect of NRIs and SSRIs

Question 4

Mechanism, Contraindication, S/E of Tricyclic Antidepressants (TCA)

Answer 4

Affect the reuptake of all three neurotransmitters
associated with mood:

1. Serotonin
2. Norepinephrine
3. Dopamine.

Adverse effects
Anticholinergic effects
→ Dry mouth, constipation, urinary retention, blurred vision, confusion
Antiadrenergic effects
→ Sedation, sexual dysfunction, orthostatic hypotension, cardiac effects
Antihistaminic effects
→Weight gain, sedation

substrates of the CYP2D6 system,

Question 5

Mechanism, Contraindication, S/E of

Serotonin antagonist-reuptake inhibitor (SARI)

Answer 5

Trazodone
MoA
5-HT2A antagonism.
→5HT2A receptors increase in depressive
patients
→ Its activation impairs the release of
neurotransmitters
→block serotonin
reuptake transporter (SERT)

Converted to mCPP and activates 5-HT1A
→Agonist actions of serotonin
specifically upon 5-HT1A receptors →
antidepressant effects.

Question 6

Mechanism, Contraindication, S/E of α2 adrenoceptor antagonist (NASA)

Answer 6

Mianserin

Blocks α2 presynatpic
autoreceptor (not transporter)
→→ suppresses the negative feedback thus enhances noradrenaline release.

Adverse Effects:
Sedation
Dry mouth
Dizziness
Vertigo

Question 7

Mechanism, Contraindication, S/E of Monoamine Oxidase Inhibitors

Answer 7

MoA
Increase levels of all three neurotransmitters by inhibiting an enzyme responsible for degrading them

Selective MAOAI
Moclobemide

Non-selective MAOI
Phenelzine
Tranylcypromine

S/E
→Orthostatic hypotension
→ Weight gain
→ Insomnia
→ Restlessness
→ Confusion

Question 8

Mechanism, Contraindication, S/E of Melatonin receptor agonist

Answer 8

Agomelatine
a synthetic version of melatonin
→a hormone that is important for regulation sleep.

MoA
→Act on melatonin receptor and also serotonin receptor (5-HT2c receptors) increses concnetraotin of dopamien and norepinephrine

Side effects
derangement in liver function
requires regular liver function
monitoring.