Antidepressants and Anxiolytics

Question 1

What is the underlying mechanism of action for SSRI’s?

Answer 1

Selectively inhibit reuptake of 5-HT (serotonin) from synaptic cleft

Question 2

What are the side-effects of SSRI’s?

Answer 2

GI- Nausea, vomiting, dyspepsia (indigestion)

CNS- Dizziness, agitation, insomnia, headache

Spinal- sexual dysfunction

Misc- Dry mouth, bleeding disorders, weight loss, hyponatremia (low sodium) in elderly

Can cause transient increase in suicidal ideation especially in <25yrs

Question 3

What are the side-effects of discontinuing SSRI’s?

Answer 3

Mood change

Dizziness

Nausea

Diarrhoea

Headache

Question 4

What are the 3 main SSRI types?

Answer 4

Citalopram

Fluoxetine

Sertraline

Question 5

Which SSRI can affect an ECG reading and how?

Answer 5

Citalopram

Dose dependent QT prolongation (Long-QT → Torsades des Pointes)

Question 6

Which SSRI is typically used first line for anxiety disorders?

Answer 6

Sertraline

Good cardiac safety profile(e.g. post-MI), commonly used first for anxiety disorders

Question 7

Which SSRI has the longest half-life and is also the only one licensed for under 18’s?

Answer 7

Fluoxetine

Question 8

If on Warfarin, NICE recommends using mirtazapine instead of SSRI’s. True/false?

Answer 8

True

Question 9

What is the underlying mechanism of action for SNRI?

Answer 9

Blocks SERT (serotonin transporter) and NET (norepinephrine transporter).

Question 10

Side effects of SNRI’s?

Answer 10

Same side effects as SSRIs + hypertension, tachycardia, QTc prolongation

Question 11

Examples of SNRI’s?

Answer 11

Venlafaxine

Duloxetine

Question 12

Apart from anxiety and depression related, what other things can the SNRI duloxetine be used for?

Answer 12

Also good also for neuropathic pain and stress incontinence

Question 13

What depressive symptoms is venlafaxine good for treating?

Answer 13

Anhedonia /anergia symptoms

Anergia = abnormal lack of energy

Anhedonia = abnormal loss of ability to feel pleasure when usually pleasure is felt.

Question 14

What is the underlying mechanism of action for mirtazapine?

Answer 14

NaSSA (antagonises a2-adrenergic + selective serotonin receptors, also histamine)

Question 15

What are symptomatic features of mirtazapine that enable it to combat SSRI side-effects?

Answer 15

Increased sleep and increased appetite, to be taken at night.

Question 16

Why is mirtazapine commonly given alongside SSRI’s?

Answer 16

Mirtazapine promotes increased sleep and increased appetite.

This helps reduce the side-effects of SSRI’s (i.e. indigestion, vomiting and insomnia).

Question 17

Trazodone has an SSRI kind of action. True/false?

Answer 17

False

SNRI kind of action

Question 18

Why is trazodone used more commonly in the elderly?

Answer 18

Used more in elderly due to sedative properties and minimal anticholinergic side-effects.

Question 19

What drug can also be used in frontotemporal dementia?

Answer 19

Trazodone

Question 20

What hormones do tricyclic antidepressants act on?

Answer 20

Serotonin and noradrenaline (similar mechanism to SNRI’s)

Question 21

What are the side effects of tricyclic antidepressants?

Answer 21

Anticholinergic (Drowsiness, dry mouth, blurred vision, constipation, urinary retention)

QT prolongation

Orthostatic Hypotension

Cardiotoxic in overdose

Question 22

Why are tricyclines commonly used in 3rd/4th line treatment?

Answer 22

Due to toxicity in overdose plus side effects

Question 23

Examples of tricyclic antidepressants (usually ends in -ine)?

Answer 23

Imipramine

Amitriptyline

Clomipramine

Question 24

Which tricyclic antidepressant functions well in OCD management?

Answer 24

Clomipramine

Question 25

What is the “cheese reaction” in monoamine oxidase inhibitors?

What are some other foods that should be stopped with this med?

Answer 25

Hypertensive crisis caused by inhibition of MAO-A in GI tract, stops breakdown of dietary tyramine

Foods containing tyramine include cheese, smoked meats, red wine, beer

Question 26

Examples of reversible and irreversible MAO-A inhibitors?

Answer 26

Irreversible- e.g. Phenelzine,

Reversible- e.g. Moclobemide (has less strict dietary requirements)

Question 27

What is GABA (Gamma-aminobutyric acid)?

Answer 27

GABA is a neurotransmitter, which means it’s a chemical messenger in the brain.

It’s one of the main inhibitory neurotransmitters, meaning it helps to calm down or inhibit the activity of nerve cells in the brain.

Question 28

What do benzodiazepines do to the neurotransmitter GABA in the brain?

Answer 28

Benzodiazepines enhance the activity of GABA in the brain, leading to calming and relaxing effects.

GABA itself is a neurotransmitter that helps to inhibit the activity of nerve cells, promoting feelings of relaxation and reducing anxiety.

Question 29

How do benzodiazepines reduce the neuronal firing?

Answer 29

By increasing the Cl- that enter the neurons.

Question 30

What are the main problems associated with benzodiazepines?

Answer 30

Patients can develop tolerance and are addictive

Avoid in pregnancy - risk of foetal malformation, “floppy baby syndrome”

Associated lethargy with breastfeeding

Increases falls risk, can worsen delirium

Withdrawal syndrome similar to alcohol withdrawal (similar mechanism)

Question 31

What are benzodiazepines used first line in?

Answer 31

Catatonia (abnormality of movement due to disturbed mental state-typically schizophrenia).

Status Epilepticus (e.g. buccal midazolam)

Question 32

What is the difference between reversible and irreversible MAO-A inhibitors?

Answer 32

Reversible: Bind to the MAO-A enzyme temporarily and can be displaced by other molecules.
They inhibit the activity of MAO-A while they are bound to the enzyme but do not permanently alter the enzyme’s structure.

Irreversible: Bind irreversibly to the MAO-A enzyme, forming a covalent bond that permanently alters the enzyme’s structure.
Once bound, irreversible MAO-A inhibitors permanently inhibit the activity of the enzyme.