Antidepressants Flashcards
Antidepressant Medication Basics
what is the biochemical name for serotonin?
5-hydroxytryptamine
what functions is serotonin involved in?
mood, sleep, memory, fear, stress response, libido, digestion, body temperature
what type of substance is serotonin?
monoamine neurotransmitter
what are the names of three monoamine neurotransmitters?
serotonin, noradrenaline, dopamine
how do SSRIs work?
inhibit reuptake of serotonin at 5-HT(1A and 2A) receptors
what does SSRI stand for?
selective serotonin reuptake inhibitor
what are the side effects of antidepressant medications?
headache, agitation, dizziness, blurred vision, sleeping difficulties (insomnia or drowsiness), reduced libido, GI upset, erectile dysfunction, weight gain
give some examples of SSRIs
sertraline, citalopram, escitalopram, paroxetine, fluoxetine
what does MAOI stand for?
monoamine oxidase inhibitor
what was the first type of antidepressant to be developed?
monoamine oxidase inhibitors
give some examples of MAOIs
phenelzine, selegiline, isocarboxazid
what is the cheese reaction?
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
how do MAOIs work?
inhibit monoamine oxidase, which usually breaks down serotonin, dopamine, and noradrenaline
why are MAOIs not often used these days?
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
what is serotonin syndrome?
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
what are examples of SNRIs?
venlafaxine, duloxetine
how do TCAs work?
prevent re-uptake of serotonin and noradrenaline
what are the side effects of TCAs?
dry mouth, constipation, blurred vision, drowsiness, dizziness, sweating, arrhythmias, weight gain
(anticholinergic effects as they block antimuscarinic receptors)
give some examples of TCAs
amitriptyline, nortriptyline, imipramine
how is serotonin syndrome treated?
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
what type of drug is procyclidine?
anticholinergic
what does procyclidine do?
anticholinergic often used to relieve symptoms of Parksinson’s and extrapyrimidal side effects of antipsychotic medications (muscle stiffness, dystonia, akathisia)
what is lithium used for?
1) mood stabiliser
2) can help with bipolar disorder, mania, and depression
what are the side effects of lithium?
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
how should patients taking lithium be monitored?
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
what type of drug is topiramate?
1) antiepileptic
2) can also be used to prevent migraine
why are TCAs less commonly used for depression these days?
1) side effects
- antimuscarinic (dry mouth, blurred vision, urinary retention, constipation)
- anti-adrenergic (postural hypotension)
- anti-histaminic (drowsiness)
- QT prolongation
2) toxic in overdose
what is normal QT interval?
<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)
why is prolonged QT interval dangerous?
risk of ventricular arrythmia (especially torsades de pointes), syncope, and death
what does the QT interval represent?
ventricles contracting and recovering (start of QRS to end of T-wave)
what is the relationship between QT interval and heart rate?
inversely proportional
- faster HR = shorted QT
- slower HR = longer QT
which psychiatric medications cause prolonged QT interval?
- most antipsychotics
- SSRIs, TCAs, SNRIs, MAOIs
what is torsades de pointes?
rare but potentially fatal type of ventricular arrythmia, usually occurs in QT prolongation
what type of drug is bupropion?
noradrenaline dopamine reuptake inhibitor
what drug class is trazodone?
serotonin antagonist and reuptake inhibitor
(net positive increase in serotonin due to inhibition of reuptake. antagonism is at certain sites and helps reduce side effects such as anxiety and agitation.)
Good Job! :)
what is a CGI score?
clinical global impressions scale that assesses severity of illness, global improvement, and therapeutic response
7-point scale with 1 being normal and 7 being severely ill
what is QIDS-SR?
quick inventory of depressive symptoms (self-rating version)
