Antidepressant Drugs Flashcards
what is prescribed for all levels of depression
Psychotherapy
- CBT
- lifestyle changes
- establishing routine
when starting an antidepressant, how long do you wait to see if it improves symptoms
4 weeks
if there has been no improvement after 4 weeks, what do you do?
change the drug
if there as been some improvement after 4 weeks, what do you do?
re-evaluate after another 4 weeks
how long should you stay on an antidepressant after improvement
at least 6 months - 1 year
which antidepressant is usually first line
SSRIs
selective serotonin reuptake inhibitors
mechanism of action of SSRIs
block reuptake of serotonin into presynaptic cell – increase serotonin in the synaptic cleft
examples of SSRIs
fluoxetine
citalopram
sertraline
paroxetine
how long do SSRI’s take to work
2-3 weeks
which SSRI is best in adolescents
fluoxetine
what pathway does fluoxetine block
CYP450
which SSRI is best in epileptic patients
citalopram
which SSRI is safest in cardiac patients
sertraline
what drugs are contraindicated with SSRIs
triptans
NSAIDS
aspirin
warfarin
side effects of SSRI’s
GI upset nausea headache insomnia sweating sexual dysfunction vivid dreams worsened anxiety for first few days
risk of SSRIs in younger patients
can increase risk of self harm in first few weeks
side effect of SSRIs in the elderly
hyponatraemia
confusion, lethargy, nausea, headache, seizures
when should SSRIs be taken and why
in the morning to reduce the effect on insomnia
mode of action of TCAs (tricyclic antidepressants)
block the reuptake of serotonin + noradrenaline into presynaptic terminals
which receptors do TCAs also block
muscarinic receptors , alpha adrenoreceptors and histamine receptors — leads to unwanted side effects
examples of TCAs
amitriptyline
imipramine
lofepramine
anticholinergic side effects of TCAs
blurred vision dry mouth constipation urinary retention weight gain
cardiovascular effects of TCAs
tachycardia
arrhythmia – prolonged QT
cardiotoxicity in overdose
when are TCAs taken and why
at night due to side effect of sedation
why should TCAs be avoided in patients with suicidal attempt
very dangerous in overdose – cardiotoxicity
anti-adrenergic side effect of TCAs
postural hypotension
what ECG changes can be seen with TCAs
Long QT interval
ST elevation
contraindications for TCAs
recent MI arrythmias severe liver disease mania high risk of overdose
mode of action of MAOIs (monoamine oxidase inhibitors)
slows breakdown of noradrenaline, serotonin and dopamine by inhibiting the mitochondrial enzymes monoamine oxidase A and B
which MAOI displays irreversible inhibition
phenelzine
which MAOI displays reversible inhibition
moclobemide
when are MAOIs used
atypical depression
3/4th line in resistant depression
side effects of MAOIs
hypertensive crisis
serotonin syndrome
what leads to a hypertensive crisis with use of a MAOI
MAOIs inhibit MAO-A in the gut and the liver - the enzyme usually breaks down dietary tyramine
build up of tyramine (from diet) increases noradrenaline causing vasoconstriction – hypertension
symptoms of hypertensive crisis
headache, SOB, flushing, high BP, anxiety, arrhythmia
treatment of hypertensive crisis
alpha blockade – phentolamine
what foods must patients avoid on a MAOI
foods rich in tyramine
- cheese
- yoghurt
- alcohol
- meat
- yeast
what causes serotonin syndrome
if a MAOI is combined with another anti-depressant
signs of serotonin syndrome
neuromuscular abnormalities
altered conscious level
autonomic instability
contraindications of MAOIs
cerebrovascular disease
pheochromocytoma
hepatic impairment
examples of serotonin noradrenaline reuptake inhibitors (SNRIs)
venlafaxine
duloxetine
what can duloxetine be used for other than depression
neuropathic pain
stress incontinence
example of an NaSSA
mirtazapine
when is mirtazapine used
first line if patient has a poor appetite / insomnia
side effects of mirtazapine
increased appetite weight gain sedation tremor peripheral oedema
what is given with sexual dysfunction caused by SSRI
trazodone
prior to starting ECT, how should antidepressant doses be adjusted
decrease dose gradually before starting ECT
short term side effects of ECT
headache
nausea
short term memory impairment
cardiac arrhythmias
complications of SSRIs used in
- 1st trimester
- 3rd trimester
1st trimester = congenital heart defects
3rd trimester = persistent pulmonary HTN
