antidepressants Flashcards
Antidepressants increase the level of monoamine neurotransmitters, name 3
serotonin
norepinephrine
dopamine
describe the transmission process of the 3 monoamine neurotransmitters
produced in respective presynaptic neurones
released to activate respective receptors on postsynaptic neurones
action is terminated via removal from synaptic cleft by protein transporters which take neurotransmitters back to presynaptic neurones
a portion are recycled and rest are degraded by enzyme - monoamine oxidase (MAO)
where do most antidepressants act?
inhibit the reuptake of monoamine neurotransmitters or their degradation by MAO
how many classes of antidepressants are there?
5
name the 5 classes of antidepressants
SSRIs
SNRIs
TCAs
MAOIs
Atypicals
how do SSRIs work and why are they drug of choice for depression?
they inhibit the reuptake of serotonin therefore increasing serotonin levels in the synapse
only act on serotonin therefore less side effects
give some examples of SSRIs
citalopram
fluoxetine
sertraline
fluvoxamine
paroxetine
how do SNRIs work?
inhibit reuptake of serotonin and norepinephrine
different drugs in this class exhibit different levels of selectivity among the two chemicals
name some examples of SNRIs
venlafaxine
duloxetine
desvanlafaxine
(above favour serotonin, below favour norepinephrine)
milnacipran
levomilnacipran
how do TCAs work and what are some side effects due to this?
similarly to SNRIs, inhibit both serotonin and norepinephrine reuptake
also act on histamine (H1) and muscarinic (M1) receptors.
causes sedation and anticholinergic effects
what are some other indications of TCAs and contraindication?
also used for migraine prevention and neuropathic pain
contraindicated in CVD
name some examples of TCAs
amitriptyline
clomipramine
dosulepin
imipramine
how do MAOIs work?
inhibit MAO enzymes A and B which prevents breakdown of serotonin, norepinephrine and dopamine and increases levels of all 3 in the synapse.
what is a problem with MAOIs?
because it inhibits MAO A and B which are also present in the digestive system where they breakdown monoamines in food, it causes a drug-food interaction so its use is avoided in depression.
an accumulation of monoamines in the GI system can cause a rapid and dangerous rise in BP
therefore, patients need to avoid tyramine-rich foods such as cheese, pickles, cured meats, etc
name some examples of MAOIs
tranylcypromine
phenelzine
selegiline
moclobemide
isocarboxazide
