Antidepressants Flashcards
4 classes of antidepressants
tricyclics, SSRIs, MAOIs and SNRIs
main problem with TCAs
many side effects
3 categories of TCA side effects
antihistaminic, anticholinergic and antiadrenergic
sedation and weight gain are what category of side effects
antihistaminic
a dry mouth, dry eyes, constipation, memory deficits and delirium are what category of side effet
anticholinergic
antiadrenergic side effects
orthostatic hypotension, sedation and sexual dysfunction
two causes of the sedation side effect in TCAs
antihistaminic and antiadrenergic
two types of TCAs
tertiary and secondary (secondaries are metabolite of tertiaries)
mechanism of tertiary TCAs
block reabsorption of serotonin
mechanism of secondary TCAs
block noradrenaline reabsorption
what type of drug is amitryptyline
a tertiary TCA
what type of drug is desipramine
a secondary TCA
which class of drugs affects the QT interval
TCAs - lengthen QT interval
which type of TCA has more severe side effects
tertiary
5 side effects of TCAs
weight gain, sedation, orthostatic hypotension, constipation, dry mouth
what does MAOI stand for
monoamine oxidase inhibitor
main indication for MAOI use in depression
treatment resistant depression
mechanism of MAOIs
binds to monoamine oxidase preventing its inactivation of the neurotransmitters NA, dopamine and serotonin
what type of drugs are isocarboxazid and selegiline
MAOIs
2 main side effects to look out for in MAOIs
cheese reaction and serotonin syndrom
what drugs do the “cheese reaction” occur in and what is it
MAOIs - a hypertensive crisis occuring when you eat tyramine rich foods like cheese or sympathomimetics
side effects of MAOIs aside from cheese reaction
serotonin syndrome weight gain dry mouth sedation sexual dysfunction sleep distrurbance orthostatic hypotension
what happens in serotonic syndrome
drug that increases serotonin –> dangerously high serotonin –> abdominal pain, diarrhoea, sweats, tachycardia, HTN, myoclonus, irritability and delirium –> in severe CV shock and death
how to prevent serotonin syndrome
wait 2 weeks before switching SSRI to MAOI or 5 weeks for fluoxetine to MAOI
what does SSRI stand for
selective serotonin reuptake inhibitor
mechanism of SSRIs
block presynaptic serotonin reuptake
what is the most commonly prescribed type of antidepressant
SSRI
paroxetine, sertaline and fluoxetine, citalopram, escitalopram and fluvoxamine are what type of antidepressant
SSRI
what is activation syndrome
restlessness, agitation and anxiety during inital weeks of treatment, especially in under 25s
what drug type do you get activation syndrome and discontinuation syndrome in
SSRIs
what is discontinuation syndrome
agitation, nausea and dysphoria when you stop SSRIs. Not withdrawal because it’s not a craving for the drug
which drug classes have the most risk of sexual dysfunction
SSRIs and SNRIs - in >30%
which 2 SSRIs lengthens QT interval
citalopram and escitalopram (the prams)
relationship between half-life and build-up of a drug
Longer half-life increases build-up. As does an active metabolite
which SSRI has a long half-life making is less likely to induce discontinuation syndrome
fluoxetine
what is the first line type of antidepressants
SSRI
general side effects from SSRIs
gi upset, increased risk of gi bleed and agitation/anxiety
fluoxetine and paroxetine has a high propensity for _______
DDIs
given the gi risks of SSRIs what drug should be prescribed along side it if the patient takes NSAIDs
PPI
mechanism of SNRIs
inhibit serotonin and NA reuptake
main difference between TCAs and SNRIs
SNRIs don’t have the anticholinergic, antiadrenergic or antihistaminic side effects of TCAs
two SNRIs
venlafaxine and duloxetine
indications of SNRIs
anxiety, depression and neurpathic pain
side effects of venlafaxine
lengthens QT interval raises diastolic BP significan nausea sexual dysfunction bad discontinuation syndrome
good things about venlafaxine
short half-life and fast renal clearance making it good in elderly
low DDIs
which SNRI raises diastolic BP more, venlafaxine or duloxetine
venlafaxine
pros of duloxetine
good for physical symptoms of depression
less effect on diastolic BP
how much does mirtazapine raise cholesterol by
~20%
what type of side effects make mirtazapine sedating and cause weight gain
antihistaminic
which drug is also a 2nd line in ADHD
buproprion
buproprion has an increased risk of ______ and can induce ______ and ______
seizures, anxiety and psychosis
for a treatment naive patient what drug type should you start them on
an SSRI
how to treat treatment resistant depression
combination of antidepressants
adjunct with lithium
adjunct with atypical antipsychotic
ECT
how long do you continue antidepressant treatment for after a 1st episode
6-12 months
how long do you continue antidepressant treatment after a 2nd episode
2 years
how long do you continue antidepressant treatment after a 3rd episode
consider life-long