Anti-depressants Flashcards
Anti-depressant uses
Major depression Persistent depressive disorder Anxiety Disorders Trauma and Stressor Related Disorders Obsessive Compulsive Disorder Eating Disorders
MAOIs (Monoamine Oxidase Inhibitors)
Tranylcypromine
Phenelzine
Isocarboxazid
Selegiline
“MAO Takes Pride in Shanghai”
TCAs (Tricyclic Antidepressants)
Amitriptyline Nortriptyline Doxepin Imipramine Desipramine Clomipramine
SSRIs (Selective Serotonin Reuptake Inhibitors)
Fluoxetine Sertraline Paroxetine Citalopram Escitalopram Fluvozamine
SNRIs (Serotonin Norepinephrine Reuptake Inhibitors)
Venlavaxine
Desvenlafaxine
Duloxetine
Atypical Antidepressants
Mitazepine Buproprion Nefazodone Vilazodone Vortioxetine
Noradrenergic and serotoneric alpha 2 adrenergic antagonist
Mitazepine
NDRI: Norepinephrine and Dopamine reuptake inhibitor
Buproprion
Serotonin/NE reuptake inhibitor and serotonin 2A antagonist
Nefazodone
Serotonin reuptake blockade and serotonin 1A partial agonist
Vilazodone
Vortioxetine
MAOI MOA
Block the break down of serotonin, NE, and dopamine by MAO inside the presynaptic terminal
MAO-A MOA
metabolizes catecholamine (NE, Epi), 5HT metabolizes tyramine and DA
MAO-B MOA
metabolizes trace amines and 5HT (at high concentrations)
Metabolizes tyramine and DA
MAO irreversible inhibitors
Phenelzine
Tranylcypromine
Selegiline
MAOI irreversible inhibitor MOA
Phenelzine, Tranylcypromine
Block MAO-A and MAO B by covalently binding the enzyme, permanently disables the enzyme
MAOI irreversible inhibitor MOA
Selegiline
Preferentially inhibits MAO-B
At high doses can inhibit MAO-A
How long does it take an MAO enzyme to be replaced after irreversible inhibitors are stopped
10-14 days
How long does it take an MAO enzyme to be replaced after reversible inhibitors are stopped?
1 day
MAOI reversible inhibitors
RIMAs: reversible inhibitors of monoamine oxidase
Meclobemide
NOT FDA approved in the US
MAOI half-life
brief
MAOI side effects
Due to excess serotonin and NE GI (nausea, constipation, appetite change) Sleep disturbances Sexual dysfunction Sedation Weight gain *Hypertensive Crisis *Serotonin Syndrome
MOAI Hypertensive Crisis
Increased NE system
- Food with high amounts of tyramine (aged cheeses, wines, cured meats); tyramine is metabolized by MAO, unmetabolized tyramine is a pressor
- Sympathomimetics (cold medicine)
- cocaine, ecstasy, opioids
How does Selegiline protect against a hypertensive crisis when given as a transdermal patch?
Drug goes 1st to brain (higher dose for anti-depressant effect), goes through 1st pass in liver, then goes to GI (lower dose)
MOAI Serotonin Syndrome
Increased Serotonin system
If give combo of MAOIs and SSRIs, SNRIs, or TCAs: prevent metabolism of serotonin and reuptake of serotonin > excess serotonin
-Increased reflexes, myoclonus, autonomic dysfunction (unstable BP, increased temp, disorientation)
Food restrictions with MAOIs (severe):
Aged cheeses Aged meats All beers on tap Sauerkraut Fava or broad bean pods Banana peels Soy sauce
Food restrictions with MAOIs (Moderation):
Red wine (4 oz) White wine (4 oz) Bottle or canned beer (12 oz)
Food restrictions with MAOIs (mild to none):
Fresh/processed cheeses Fresh or processed meats Bouillon Chocolate Avocados Banana pulp
Which drugs put you at risk for Serotonin Syndrome when combined with a MAOI?
Analgesics/Opioids: Meperidine, Methadone, Pentazocine, Tramadol (weak serotonin reuptake inhibitors)
Antidepressants: Mirtazepine, SNRIs, TCAs, SSRIs
OTC cold remedy: Dextromethorphan (weak serotonin reuptake inhibitor)
Which drugs put you at risk for Hypertensive crisis when combined with a MAOI?
Analgesics/opioids: Tramadol
Antidepressants: Buproprion, Other MAOIs, Mirtazepine, SNRIs, TCAs
Sympathomimetics
OTC cold remedies
Indication for MAOIs
Treatment resistant depression
Treatment resistant anxiety disorders
Treatment resistant atypical depression
Not used much anymore due to SE
TCAs: Tricyclic Antidepressant MOA
NE and Serotonin reuptake inhibitors
Also block histamine, acetylcholine, alpha adrenergic receptors!
What is the secondary TCA metabolite of Imipramine?
Desipramine
What is the secondary TCA metabolite of Amitriptyline?
Nortriptyline
Tertiary TCA metabolite MOA
NE= 5-HT reuptake inhibitor
Secondary TCA metabolite MOA
NE > 5-HT reuptake inhibitor
What is unique about Clomipramine and Doxepine TCAs?
Tertiary but act like secondary
TCA Pharmacokinetics
High lipid solubility High protein binding Large volume of distribution Rapid absorption Significant 1st pass metabolism
TCA side effects
Block H1 rec: sedation, weight gain Block M1 rec: sedation, confusion, blurred vision, dry mouth, constipation Block a1 rec: sedation Increased serotonin: sexual dysfunction Increased NE: increased BP, sweating
TCA Contraindications
Elderly (65+) - risk of sedation and confusion, avoid polypharmacy
CNS depressants: alcohol, barbituates, opiates, benzodiazepines
Overdose- hypotension, respiratory depression, confusion, delirium, altered, severe arrhythmias
Serotonin Selective Reuptake Inhibitors (SSRIs) MOA
Selectively bind the serotonin reuptake pump (much less risk of side effects)
Which drug has the longest half life of the SSRIs?
Fluoxetine has the longest half life (7-15 days)- could take 5 weeks before completely gone!
Which SSRIs inhibit CYP450 2D6 enzymes?
Fluoxetine and paroxetine are strong inhibitors
Which SSRI has significantly less protein binding than the others?
Escitalopram (56%)
Which SSRIs have the shortest half lives?
Paroxetine and Fluvoxamine
Which SSRIs have the high risk for discontinuation syndrome?
Paroxetine and Fluvoxamine
Describe the relationship between Citalopram and escitalopram?
Escitalopram is purified S isomer of citalopram
Characteristics of SSRI side effects
Occur prior to onset of anti-depressant effect
Are dose dependent
May happen once, intermittently, or chronically
May have different levels of severity
Common SSRI side effects
*Due to excessive serotonin* GI Anxiety CNS Sexual Dysfunction
Symptoms of SSRI discontinuation syndrome
Dizziness, nausea, fatigue, headache, insomnia, restlessness, unstable gait, brain zaps
Serotonin Norepinephrine Reuptake Inhibitors (SNRIs)
Blocks serotonin and NE reuptake pumps
At high dose can block dopamine reuptake pump
What is the most commonly used SNRI?
Venlafaxine
Which SSRI has the highest affinity for the 5-HT transporter?
Paroxetine
Which SSRI is the least 5-HT selective?
Fluoxetine
Which SSRI is most likely to have drug-drug interactions due to inhibition of CYP enzymes?
Fluvoxamine
Which SNRI has the shortest half life?
Venlafaxine
Which SNRI has the greatest risk of causing discontinuation syndrome if stopped abruptly?
Venlafaxine
also Desvenlafaxine
What is the metabolite of Venlafaxine?
Desvenlafaxine
Mirtazapine MOA
Block a-2 presynaptic autoreceptors on NE and 5HT neurons, leads to increased NE and 5HT
Also blocks Histamine, 5HT2A, 5HT2C, 5HT3
Mirtazapine Side effects (or lack thereof…)
Block histamine: weight gain, dry mouth, sedation
Block 5HT2A, 5HT2C, 5HT3: NO nausea, NO sexual dysfunction, NO insomnia, NO anxiety!
Buproprion MOA
NE and DA reuptake inhibitor
No effects on 5HT, histamine
Burproprion side effects (or lack thereof…)
No 5HT related (sexual)
No H1 related (sedation/weight gain)
Increased seizure risk at high doses
Can Buproprion and Mirtazapine be used in combination with SSRIs and SNRIs?
Yes! Especially if you are only getting partial improvement in depression symptoms
Nefazodone MOA
Blocks 5-HT reuptake (SSRI effects)
5-HT2A receptor antagonist: no sexual side effects
Nefazodone Side effects (or lack thereof…)
Mild sedation
No sexual side effects
Vilazodone MOA
Blocks 5HT reuptake (SSRI)
Partial agonist of 5-HT1A receptors (additional help for depression/anxiety)
Vilazodone side effects (or lack thereof…)
No weight gain
No sexual side effects
GI, nausea, vomiting, diarrhea
Insomnia
Vortioxetine MOA
Blocks 5-HT reuptake (SSRI)
Agonist at 5-HT1A
Partial agonist at 5-HT1B
Antagonist at 5-HT3 (less GI) and 5-HT7
Vortioxetine side effects (or lack thereof)
No weight gain
No sexual side effects (except at high dose)
GI (nausea > vomiting/diarrhea)
After stopping an MAOI, how long to wait until starting new antidepressant?
What are you waiting for?
What if MAOI is reversible?
10-14 days
Neurons to regenerate MAO
Only need to wait 1 day
After stopping other anti-depressants, how long wait until starting MAOI?
What are you waiting for?
Are there any anti-depressants that would require a longer wait before starting MAOI?
Need to wait ~1 week (5 half life for drug to clear)
Drugs to clear
Fluoxetine (~5 weeks)
What is the risk of overlapping an anti-depressant with an MAOI?
Risk of serotonin syndrome (increased serotonin)
Risk of hypertensive crisis (increased NE)
Which drug inhibits CYP 1A2?
Fluvoxamine
Which drugs inhibit CYP2C9 and CYP2C19?
Fluvoxamine
Fluoxetine
Which drugs inhibit CYP2D6?
Paroxetine
Fluoxetine
Buproprion
Which drugs inhibit CUP3A4?
Nefazadone
Fluxoxamine
Which 2 drugs are the MOST likely to produce interactions with other drugs?
Fluvoxamine
Fluoxetine