Antidepressants Flashcards
How do MAOIs work?
Irreversible inhibitors of MAO in presynaptic neurons which leads to increase in 5-HT (serotonin), dopamine, and norepi
What is the major side effect of MAOIs?
Tyramine-induced hypertensive crisis
Dietary causes - cheese, fava beans, liver, soy sauce, sauerkraut, fermented foods, cured meats
Medical causes - cold meds, pain killers
How does tyramine induced hypertensive crisis work?
MAO breaks down tyramine in gut
When it’s not broken down, it has adrenergic properties
Sudden catastrophic rise in BP
What are the contraindications to MAOIs? What can it lead to?
Co-administration with any other antidepressant except for TCAs
Serotonin syndrome
What are the 4 MAOIs?
Phenelzine (Nardil)
Tranylcypromine (Parnate)
Isocarboxazid (Marplan)
Selegeline (Emsam)
What are the minor side effects of MAOIs
Most common = adrenergic - orthostatic hypotension Second most common = insomnia weight gain sexual dysfunction mania
How do TCAs work?
Antagonist at presynaptic 5-HT and NE reuptake pumps
Increases serotonin and NE in the synapse
How long do TCAs take to work?
3-4 weeks after initiation
What are the tertiary amine TCA drugs?
Amitriptyline (Elavil) Clomipramine (Anafranil) Doxepin (Sinequan) Trimipramine (Surmontil) Imipramine (Tofranil)
What are the side effects of tertiary amine TCAs?
More anticholinergic, histaminergic, and adrenergic side effects
More dangerous in overdose
What are the secondary amine TCA drugs?
Desipramine (Norpramin)
Nortriptyline (Pamelor)
Protriptyline (Vivactil)
What are the side effects of secondary amine TCAs?
Less anticholinergic/histaminergic/adrenergic = less sedation and less orthostatic hypotension than tertiary
What are the characteristics of TCAs?
Highly protein bound - will interact with other protein bound drugs
Highly anticholinergic
Causes QTc prolongation
Sexual dysfunction
What are contraindications to TCAs?
Cardiac conduction delays
Arrhythmias
BPH - causes urinary retention and post void residual, leading to UTIs
What are the serious side effects of TCAs?
Lethal in overdose
Cardiotoxic = widened QRS, prolonged QTc, AV block, torsades
Neurotoxic = tremor, ataxia, delirium, coma, seizures
What are the 3 C’s of TCA overdose?
Convulsions
Coma
Cardiotoxicity
Treatment for TCA overdose?
Sodium Bicarb, Mg
How do SSRIs work?
Antagonist at presynaptic 5-HT reuptake pump
How long do SSRIs take to work?
3-4 weeks after initiation
What if you want to switch from MAOI to SSRI?
2 week washout in between
What are the contraindications of SSRIs?
Concurrent use with MAOIs –> serotonin syndrome
What are the signs of serotonin syndrome? What is the treatment of serotonin syndrome?
Hyperthermia Myoclonus Autonomic instability Rigidity Coma Death
Treatment = cyproheptatine = serotonin receptor antagonist
What are minor side effects of SSRIs?
5-HT3 = GI, N/V/D
5-HT2C = anxiety and agitation
5-HT2A = anxiety, agitation, akathisia, insomnia, sexual dysfunction
Serotonin discontinuation = headache, dizziness, irritability, fatigue
weight gain
mania
Rare hyponatremia
What is the mechanism of SNRIs?
Antagonism at presynaptic 5-HT and NE reuptake
At higher doses, also inhibits DA reuptake
How do SNRIs and TCAs differ?
SNRIs have no anticholinergic, antihistaminergic, and antiadrenergic effects
What are the side effects of SNRIs
Increased NE = tachycardia, hypertension, agitation, anxiety, akathisia, tremor, myoclonus
Increased serotonin = GI symptoms, sexual dysfunction
Insomnia
Rare seizures
Contradication = concurrent MAOI for serotonin syndrome
What are are the SSRI drugs?
Fluoxetine (Prozac/Sarafem) Paroxetine (Paxil) Sertraline (Zoloft) Fluvoxamine (Luvox) Citalopram (Celexa) Escitalopram (Lexapro)
What are the SNRI drugs?
Venlafexine (Effexor)
Duloxetine (Cymbalta)
Desvenlafexine (Pristiq)
How do NaSSAs work?
Noradrenergic and Specific Serotonergic Antidepressant
Antagonist at alpha2 adrenergic receptors = disinhibits NE and 5HT release
Agonist at alpha 1 = increases 5HT release
How do SARIs work?
Serotonin Antagnoists and reuptake inhibitors
Antagonist at presynaptic 5HT reuptake pump
Antagonist at post-synaptic 5-HT2A receptors = no sexual side effects!
How do NDRIs work?
Antagonist at presynaptic NE and DA reuptake pumps
