Pharmacology of Antidepressants Flashcards
which drugs have the most effect in moderate depression
most of the drugs have a similar effect
which drugs are most effective in severe depression
TCAs
what are teh 3 cardinal symptoms of depression
anergia, low mood and anhedonia
outline the criteria for mild, moderate and severe depression
do AD work immediately?
no, take around 2-6 weeks
how long do depressive symptoms need to be present for for crtieria?
most of teh day for the past 2 weeks
are dosing adjustments amde for older patients?
yes, they dont need as large as an adult dose
usually start on half the adult dose
what happens if you start a patient on an AD and see no change?
assess after 4-6 weeks
increase dose and review in 2 weeks
if after 6 weeks at max/max tolerated dose there is still non/inadequate response - switch drug
if eg fluxoetine doesnt work cn you switch to citalopram?
no, must swittch AD class
how long after resolutionof symptoms must AD be continued for, and after recurrence
6-12 months
12-24 if recurrence
what happens if you stop AD too soon?
50% relapse
in which circumstances would AD be continued indefinitely?
3rd relapse, or very severe
what is the monoamine hypothesis
suggests that depression results from functionally deficient monoaminergic transmission in the CNS. although this is too simple to fully explain depression, pharmacological theory is based on increasing the monoaminergic transmission
endocrinology and depression
dexamethasone suppression test is abnormal in 1/3 patients - abnormally weak response of plasma cortisol to exogenous steroid
this may reflect monomaine transmission in the hypothalamus
what is the first derivative of serotonin
tyrptophan
what is noradrenaline made from
what is the role of monoamine oxidase enzyme
removes the neurotransmitters norpinehrine, serotonin and dopamine from the brain by reabsorbing them from teh synpatic clefr and breaking them down
mechanism of action of SSRIs
selectively inhibit the reuptake of serotonin from the synaptic cleft
which drug is used first line in depression
usually SSRI, individuals respond differently to different drugs
when are SSRIs taken
morning, reduce insomnia
use of SSRIs in teh elderly
avoid! they cause hyponatraemia and falls
SSRIs and sexual function
can cause sexual dysfunction and failure of orgasm
what effect do SSRIs have on weight
can cause anorexia
drug for patient with depression and obesity?
fluoxetine causes weight loss
drug interactions with SSRIs
there is an increased risk of GI bleeding if taken with NSAIDs
which 2 SSRIs are best for patients who are worried about drug interactions
citalopram and sertralie have the lowest risk of interactions
are there discontinuation symptoms with SSRIs?
yes, similar to AE
myoclonus too
which SSRi is the safest in cardiac problems?
sertraline
what is there an increased risk of with SSRIs, especially in teens
transient increase in self harm or suicidal ideation, more likely in younger person
depression in the elderly
avoid SSRIs
half dose of TCA
mechanism of action of TCAs
block the reuptake of monoamines into presynaptic terminals (mainly noradrenaline and serotonin)
in which class of depresion are TCAs good
severe, and elderly
what are the main AE of TCAs
they have anticholinergic effects as block M2 and M3 receptors in smooth muscle: bladder (urinary retention), vascular and airways, blurred vision, dry mouth, constipation
do TCAs have an effect on weight?
cause weight gain
when are TCAs taken
at night - they cause sedation
what problems can teh sedation from TCA cause
daytime performance affected by drowsiness and difficulty concentrating
what are the CVS side effects of TCAs
cause postural hypotension, tachycardia and in more severe cases arrhythmias
what type of event would deem patients as having an increased arrhythmias risk, and so should avoid TCAs
eg post MI
overdose of TCAs
are cardiotoxic
initially, excitement and delirium and convulsions
cardiac dysrhythmias (heart block)
how does sudden death usually occur in TCA overdose
usually due to atrial fibrillation
why should TCAs be avoided in those with suicidal intent
due to cardiotoxicity
how do dual reuptake inhibitors work
block the reuptake of monoamines noradrenaline and 5HT into presynaptic terminals
when are dual reuptake inhibitors taken
in the morning - insomnia
what other use does duloxetine have
neuropathic pain and bladder instability (stres incontinence)
when are dual reuptake inhibitors usually used
if SSRI hasnt worked
excellent in combination with mirtazapine
in which cases may mirtazapine be considered first line
if patient has insomnia and or poor appetite
does mirtazapine have a faster or slower onset than others
faster
what substance should mirtazapine not be combined with
alcohol - can cause GI upset
trazodone
monoamine receptor antagonist
which drug can cause priapism
trazodone, MARA
