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Flashcards in Antidepressants Deck (41)
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1
Q

What are the natural and synthetic catecholamine agonists?

A
  • natural
    • epinephrine
    • norepi
    • dopamine
  • synthetic
    • isoproterenol
    • dobutamine
2
Q

The receptors that are termed alpha receptors respond to the catecholamines in what order of potency?

A

Norepi > epi > isoproterenol

3
Q

The receptors that are termed beta receptors respond to the natural and synthetic catecholamines in what order of potency?

A

Isoproterenol > epi > norepi

4
Q

What is serotonin?

Where is it found in the highest concentration?

A
  • 5-Hydroxytryptamine (5-HT)
    • neurotransmitter and local hormone
  • highest concentration:
    • wall of intestine
    • blood
    • CNS
5
Q

What are the three types of antidepressants?

A
  • Selective serotonin reuptake inhibitors
  • tricyclic antidepressants
  • Monoamine Oxidase Inhibitors
6
Q

What are SSRI’s used for?

A
  • treat mild to moderate depression
  • anxiety disorder
  • panic disorder
  • OCD
  • post-traumatic stress disorder
  • social phobia
  • bi-polar depressive episodes
7
Q

What is the MOA of SSRI’s?

A
  • All block reuptake of serotonin
  • New SSRI’s act on serotonin, NE, and/or dopamine
  • some produce alpha 2 receptor blockade
8
Q

What makes an SSRI atypical?

A

If it acts on dopamine

9
Q

What are the typical SSRIs?

A
  • Fluoxetine (prozac)
  • Sertraline (zoloft)
  • Paroxatine (paxil)
  • Fluvoxamine (Luvox)
  • Escitalopram (Lexapro)
10
Q

Which antidepresent is the most potent inhibitor of CYP450?

A

Fluoxetine (prozac)

11
Q

Why are SSRIs the anti depressant of choice?

A
  • Higher safety index than other classes
    • minimal effects on blood pressure
    • no issues with cardiac conduction
    • no changes in seizure threshold
12
Q

What are the side effects of SSRI’s?

A
  • Insomnia/ fatigue
  • agitation
  • orthostatic hypotension
  • headache
  • nausea/vomiting
  • sexual dysfunction
  • increased appetite
13
Q

What are the anesthetic considerations for SSRIs?

A
  • inhibition of CYP450
    • may increase plasma concentration of certain drugs
  • Antiplatelet activity
    • increased risk of bleeding
  • Serotonin syndrome-medication
    • confusion, fever, shivering, ataxi, diaphoresis, hyperreflexia, muscle rigidity
14
Q

What are tricyclics used to treat?

A
  • depression
  • chronic pain syndrome in lower doses
    • chemical structure is similar to local anesthetics and phenothiazines
    • inhibits overactive inflammatory response systems
    • Potentiation of endogenous opioids
15
Q

Tricyclic MOA

A
  • Blocks reuptake of serotonin and/or NE at presynaptic terminals
    • tertiary amines- inhibits serotonin and NE reuptake
    • secondary amines- inhibit NE reuptake
16
Q

What are the tertiary amine tricyclics?

A
  • Amytriptyline (elavil)
  • Imipramine (tofranil)
  • clomipramine (anafranil)
17
Q

What are the secondary amine tricyclic medications?

A
  • Desipramine (norpramin)
  • nortriptyline (pamelor)
18
Q

What are the pharmacokinetics of tricyclics?

A
  • highly lipid soluble
  • strongly PB
  • long elimination 1/2 time
    • 10-80 hours
  • metabolized in liver
  • all have active metabolites
19
Q

What are side effects of tricyclics?

A
  • Anticholinergics
    • dry mouth, tachycardia, urinary retention, ileus, slow gastric emptying
  • cardiovascular
    • orthostatic hypotension, modest increase in heart rate, depresses conduction through the atria & ventricles
  • Central nervous system
    • lower sz threshold, weakness, fatigue
  • **these effects can be fatal with overdose
20
Q

Why would you not give a tricyclic with an MAOI?

A
  • Can cause CNS toxicity
    • hyperthermia
    • sz
    • coma
21
Q

What anesthetic drugs can have potential interactions with tricyclics?

A
  • sympathomimetics
  • IA
  • anticholinergics
  • antihypertensives
  • opioids
22
Q

What should you consider when administering sympathomimetics to a patient on tricyclics

A
  • response unpredictable
  • exaggerated responses to indirect acting due to larger amounts of NE available to stimulate post synaptic receptors
    • Use lower doses of direct acting
    • decrease by 1/3
  • Book says you could use an indirect acting sympathomimetic if the patient had been on their tricyclic chronically, but that gets fuzzy and riskly. We are risk avoiders.
23
Q

What should you expect regarding your volatile anesthetics if your patient is on tricyclics?

A

may need a higher MAC because of the extra NE that is not be re-taken up (theoretical, may not translate to practice)

24
Q

What should you expect if you administer epinephrine, opioids, or barbs to a pt on tricyclics?

What is the take home?

A
  • They will have a greater response to all these meds
  • decrease dose
  • don’t forget about epi in a LA
25
Q

What should you expect if you administer anticholinergics to a pt on tricyclics?

A
  • They may have an exaggerated response
  • more likely to have post op delirium and confusion
    • glyco is better
26
Q

What does anticholinergic toxicity or central anticholinergic syndrome look like?

A
  • flushing
  • dry mouth
  • skin
  • mydriasis (pupil dilation)
27
Q

What can an overdose of tricyclics cause?

How does this present?

A
  • life threatening intractable myocardial depression or ventricular dyrshythmias
  • present as:
    • agitation
    • excitement and deliuium
    • sz
    • progresses to coma
    • resp depression
    • cardiac dyrshythmias
    • sudden death
    • hypotensive
    • anticholinergic effects
28
Q

How is a tricyclic overdose treated?

A
  • ventilatory support
  • manage CNS and cardiac toxicity
  • physostigmine for anticholinergic psychosis
  • acidosis may increase unbound drug–more dyrshythmias
    • use bicarb
29
Q

What does the MAO enzyme system deactivate?

A

dopamine

serotonin

epinephrine

norepi

30
Q

What is the MOA of MAOIs?

A
  • blocks the enzyme that metabolized biogenic amines, increasing the availability of these neurotransmitters in the CNS and PNS
  • forms a stable, irreversible complex with MAO enzyme
31
Q

Why aren’t MAOIs used often?

A
  • side effects
  • lethal in overdose
  • difficult dosing
  • pt must follow a tyramine free diet
32
Q

What are the MAO A’s?

MAO B?

A
  • MAO A
    • serotonin
    • NE
    • epi
  • MAO B
    • phenylethylamine
33
Q

What disease have we recently learned about that might be treated with an MAO B?

What should be considered in the dosing of this drug?

A
  • Parkinson’s
  • If the dose is >30 mg, it is no longer selective and will work on A enzymes as well
    • if this happens, the patients diet will matter, just like it does with an MAO A
34
Q

What are the side effects of MAOIs?

A
  • Orthostatic hypotension (especially in elderly)
  • anticholinergic like effects
  • impotence/anorgasmy
  • weight gain
  • sedation or mild stimuland effects
35
Q

What are the dietary restrictions for MAOIs?

why?

A
  • tyramine- derived from tyrosine and can act as an idirect catecholamine releasing diet
  • must follow diet that is low in tyramine
  • to avoid Hypertensive crisis, CVA
  • ex:cheese, fava beans, wine, avocado, liver, cured meats
36
Q

What drugs should you use with caution with MAOIs?

A
  • cyclic antidepressants
  • opioids
  • cold-allergy drugs
  • sympathomimetics
  • nasal decongestants
  • SSRIs
  • no meperidine
37
Q

What symptoms should patients on MAOIs report that might indicate they are experiencing a catecholamine surge?

A

serious headache

vomiting

chest pain

38
Q

Whats the deal with Demerol and pts on MAOIs?

A
  • excitatory (type 1)- caused by enhanced serotonin activity in the brain
    • agitation
    • skeletal muscle rigidity
    • hyperpyrexia
  • depressant (type 2)- slowed breakdown of meperidine
    • hypotension
    • respiratory depression
    • coma
39
Q

Anesthetic considerations for MAOIs are basically the same as for tricyclics. What are they?

A
  • caution with sympathomimetics- no direct acting!
  • caution with opioids- no demerol!
  • may need higher MAC with VA
  • minimize possibility of sympathetic nervous stimulation or drug induced hypotension
40
Q

What are the symptoms of MAOi overdose?

A
  • excessive sympathetic discharge
    • tachycardia
    • hyperthermia
    • mydriasis
    • sz–>coma
  • treatment
    • supportive care
    • maybe dantrolene
41
Q

What symptoms may be experienced when antidepressents are discontinued?

How can this be avoided?

A
  • dizziness
  • myalgias
  • parasthesia
  • irritability
  • insomnia
  • visual disturbances
  • tremors
  • lethargy
  • N/V/D
  • wean off over two weeks