Psychopharmacology of affective disorders Flashcards
classes of antidepressant
TCAs SSRI SNRI MOAI NARI (NA reuptake inhibitors) SARI (serotonin antagonist) NaSSA - Noradrenergic and specific serotonergic antidepressant
TCA MOA
serotonin and NA reuptake inhibitors
different types affect NA and serotonin to different degrees
side effects TCAs
- anticholinergic
- antihistaminic
- a1 adrenergic blockade effects
- ion channel blockade
- anxiety
- sexual dysfunction
anticholinergic s/e?
dry mouth
blurred vision
constipation
urinary retention
antihistaminic s/e
wt gain
sedation
a1 adrenergic blockade
dizziness
hypotension
ion channel blockade s/e?
cardiac arrhythmia - LQT
seizures
examples of TCAs
2y amines - nortriptaline
3y amines - amitryptaline
2nd gen - lofepramine
TCA hx
1st = imipramine 1950s and not originally antidepressants - anti-emetics derived from
advantages of TCAs
- well established in literature
- better in severe depression
- low cost
disadvantages of TCAs
- side effects
- toxicity of OD
- Narrow TI
- CVS and CNS toxins in moderate dose
SSRIs MOA
prevent reuptake of serotonin by neurons
more serotonin in synaptic cleft
agonist action at receptors
SSRI types
fluoxetine - prozac paroxetine - seroxat sertraline - lustral citalopram - cipramil excitalopram - lexapro
features of fluoxetine
can use
features of paroxetine
v short half life - no discontinuation symptoms
decreases in dose = rapid drop in levels as inhibits its own metabolism
features of sertraline
can use in OCD
can use in breast feeding (still goes into milk though)
best CVS profile - used in those with CVS risk
citalopram and escitalopram features
- dose related QTC prolongation
- max doses in >65s
- escitalopram - least interaction cyt p450 - good augmenter
s/e of SSRIs?
- GI
- headache
- agitation
- tremor
- worsening anxiety - NB make sure not mania
- insomnia
- sexual dysfunction
- increased risk of bleeding - rare
- hyponatraemia - old ladies
- suicidal ideation - rare, kids/young adults
bleeding w/ SSRIs?
UGIB
NB risk factors for bleeding
due to effect on plt function
GI probs SSRI
ND
constipation
anorexia
advantages SSRI
better tolerated than TCAs
easy dosing
safer in OD
disadvantages to SSRI
side effects - GI/sleep probs
can induce mania in patient with depression and underlying vulnerability eg fhx BPAD
serotonin syndrome
must be gradually reduced - discontinuation syndrome
what are the sx of serotonin syndrome?
agitation confusion tachycardia HTN dilated pupils muscle spasms diaphoresis diarrhoea headache severe: pyrexia, seizure, palpitations, LOC
tx serotonin syndrome?
stop drug
benzos - diazepam or lorazepam for muscle stiffness
cyproheptadine - blocks serotonin production
O2, fluids
haemodynamically stabilise
ventilation, ICU if breathing probs
MAOI MOA
irreversible inhibition of MAO-A (enzyme that metabolises serotonin/dopamine/NA/tyramine) - increased NTs at SC
types of MAOI
tranylcyrpromine - parnate
phenelzine - nardil
disadvantages to MAOI
tyramine reaction- no cheese, red wine, chocolate, game, yeast extract
can cause HTV crisis
use of MAOI
rare except in tx resistant depression
poss atypical
SNRIs MOA + examples
stops reuptake of serotonin and NA from SC
types:
venlafaxine - effexor
duloxetine (also for neuropathic pain and urinary incontinence)
advantages to SNRI
- faster onset than ssri
- similar OD profile to SSRI
- can use with mirtazapine for refractory
disadvantages of SNRI/ s/e
- dose related HTN
- GI
- headache
- tolerance issues
- discontinuation syndrome can be nasty
discontinuation syndrome?
dizzy nausea sweating stomach cramp dysaesthesias
NaSSA MOA
a2 antagonist: more serotonin and NA release
5HT2 antagonist: more sedation/anxiolytic
less sexual dysfunction
antihistaminic moa - sedation, wt gain
example of NaSSA
mirtazapine - zispin
advantages to NaSSA?
can use with other antidepressants since different MOA
can use where need wt gain and sedation
side effects NaSSA?
drowsy
wt gain
jaundice/LFTprobs
