Antidepressants

Question 1

what is the biochemical name for serotonin?

Answer 1

5-hydroxytryptamine

Question 2

what functions is serotonin involved in?

Answer 2

mood, sleep, memory, fear, stress response, libido, digestion, body temperature

Question 3

what type of substance is serotonin?

Answer 3

monoamine neurotransmitter

Question 4

what are the names of three monoamine neurotransmitters?

Answer 4

serotonin, noradrenaline, dopamine

Question 5

how do SSRIs work?

Answer 5

inhibit reuptake of serotonin at 5-HT(1A and 2A) receptors

Question 6

what does SSRI stand for?

Answer 6

selective serotonin reuptake inhibitor

Question 7

what are the side effects of antidepressant medications?

Answer 7

headache, agitation, dizziness, blurred vision, sleeping difficulties (insomnia or drowsiness), reduced libido, GI upset, erectile dysfunction, weight gain

Question 8

give some examples of SSRIs

Answer 8

sertraline, citalopram, escitalopram, paroxetine, fluoxetine

Question 9

what does MAOI stand for?

Answer 9

monoamine oxidase inhibitor

Question 10

what was the first type of antidepressant to be developed?

Answer 10

monoamine oxidase inhibitors

Question 11

give some examples of MAOIs

Answer 11

phenelzine, selegiline, isocarboxazid

Question 12

what is the cheese reaction?

Answer 12

1) Hypertensive crisis in someone taking MAOI when they ingest too much tyramine
2) Monoamine oxidase usually metabolises tyramine to noradrenaline
3) When somebody taking a MAOI and ingests tyramine (alcohol, cured meat, cheese), the tyramine isn’t broken down = elevated levels
4) Tyramine is a serotonin analogue and effects include increasing blood pressure and migraines

Question 13

how do MAOIs work?

Answer 13

inhibit monoamine oxidase, which usually breaks down serotonin, dopamine, and noradrenaline

Question 14

why are MAOIs not often used these days?

Answer 14

Poor side effect profile and safety concerns

Remember HAHA:

• Hypotension (orthostatic)
• Anticholinergic side effects (dry mouth, constipation, blurred vision)
• Hypertensive crisis (cheese reaction)
• Anxiety, agitation, anorexia

Question 15

what is serotonin syndrome?

Answer 15

1) Excess serotonin in synapses, potentially fatal, often caused by using combination therapy e.g. SSRI + MAOI
2) Results in agitation, insomnia, tachycardia, hypertension, muscle twitching, headache, diarrhoea

Question 16

what are examples of SNRIs?

Answer 16

venlafaxine, duloxetine

Question 17

how do TCAs work?

Answer 17

prevent re-uptake of serotonin and noradrenaline

Question 18

what are the side effects of TCAs?

Answer 18

dry mouth, constipation, blurred vision, drowsiness, dizziness, sweating, arrhythmias, weight gain

(anticholinergic effects as they block antimuscarinic receptors)

Question 19

give some examples of TCAs

Answer 19

amitriptyline, nortriptyline, imipramine

Question 20

how is serotonin syndrome treated?

Answer 20

1) stop culprit medication
2) conservative tx depending on signs and symptoms- benzodiazepines, antihypertensives, beta blockers, IV fluids
3) Cyproheptadine (serotonin antagonist) if above not working

Question 21

what type of drug is procyclidine?

Answer 21

anticholinergic

Question 22

what does procyclidine do?

Answer 22

anticholinergic often used to relieve symptoms of Parksinson’s and extrapyrimidal side effects of antipsychotic medications (muscle stiffness, dystonia, akathisia)

Question 23

what is lithium used for?

Answer 23

1) mood stabiliser
2) can help with bipolar disorder, mania, and depression

Question 24

what are the side effects of lithium?

Answer 24

1) GI upset- nausea, vomiting, diarrhoea
2) fine tremor
3) nephrotoxicity
4) diabetes insipidus
5) hypothyroidism
6) ECG- T-wave flattening/inversion
7) weight gain
8) IIH
9) leucocytosis
10) hyperparathyroidism and subsequent hypercalcaemia

Question 25

how should patients taking lithium be monitored?

Answer 25

1) initially check levels weekly (12 hours after dose given) until stable
2) once stable check every 3 months
3) check renal and thyroid function every 6 months

all patients should have an information booklet, alert card, and record book

Question 26

what type of drug is topiramate?

Answer 26

1) antiepileptic
2) can also be used to prevent migraine

Question 27

why are TCAs less commonly used for depression these days?

Answer 27

1) side effects
- antimuscarinic (dry mouth, blurred vision, urinary retention, constipation)
- anti-adrenergic (postural hypotension)
- anti-histaminic (drowsiness)
- QT prolongation

2) toxic in overdose

Question 28

what is normal QT interval?

Answer 28

<450ms in men
<460 in women
- if >500ms need immediate secondary care review due to risk of arrythmia and torsades de pointes
- note that should compare to baseline (<5ms from baseline not considered significant)

Question 29

why is prolonged QT interval dangerous?

Answer 29

risk of ventricular arrythmia (especially torsades de pointes), syncope, and death

Question 30

what does the QT interval represent?

Answer 30

ventricles contracting and recovering (start of QRS to end of T-wave)

Question 31

what is the relationship between QT interval and heart rate?

Answer 31

inversely proportional
- faster HR = shorted QT
- slower HR = longer QT

Question 32

which psychiatric medications cause prolonged QT interval?

Answer 32

• most antipsychotics
• SSRIs, TCAs, SNRIs, MAOIs

Question 33

what is torsades de pointes?

Answer 33

rare but potentially fatal type of ventricular arrythmia, usually occurs in QT prolongation

Question 34

what type of drug is bupropion?

Answer 34

noradrenaline dopamine reuptake inhibitor