Psych Meds Flashcards
Where is alpha-1 found and what are the effects?
Postsynaptic
Found in vasculature, heart, glands, gut
Activation causes vasoconstriction and relaxation of the GI tract
What is the order of potency between norepi, epi, and isoproterenol for alpha and beta receptors?
Alpha: Norepi>epi>isoproterenol
Beta: Isoproterenol>epi>norepi
Note: a1/b1/dop1 are found post-synaptically, a2/b2/dop2 are found pre- and post-synaptically
Where is alpha-2 found and what are the effects?
Presynaptic found in peripheral vascular smooth muscle, coronaries, brain, CNS. Activation presynaptically causes inhibition of norepi release and inhibition of sympathetic outflow leading to decreased BP and decreased HR, inhibition of CNS activity
Postsynaptic found in coronaries, CNS. Activation causes constriction and sedation and analgesia
Where is beta-1 found and what are the effects?
(post synaptic??) Myocardium, SA node, ventricular conduction system, coronaries, kidney. Activation causes increase in inotropy, chronotropy, myocardial conduction velocity, coronary relaxation, and renin release
What are the beta-2 effects and where are they found?
(pre and post synaptic??) Found in vascular, bronchial, skin, and uterine smooth muscle, coronaries, kidneys, GI tract. Activation causes vasodilation, bronchodilation, uterine relaxation, gluconeogenesis, insulin release, potassium uptake by the cells
What catecholamines do dopamine receptors interact with?
Dopamine ONLY (no other catecholamines)
Where does dopaminergic-1 work and what are the effects?
Postsynaptic, found on renal mesenteric, splenic, and coronary vessels and renal tubules, causes vasodilation (increases urine output)
Where does dopaminergic-2 work and what effects?
Presynaptic causes inhibition of norepi release
Postsynaptic may promote constriction
What is serotonin and where is it concentrated?
Serotonin is 5-HT (hydroxytryptamine), a neurotransmitter and local hormone
Highest concentration in wall of intestine, blood, and CNS
SSRI uses?
Mild- moderate depression, panic disorder, OCD, PTSD, social phobia, bipolar
SSRI mechanism of action?
Block reuptake of serotonin
New SSRI’s act on serotonin, norepinephrine, and/or dopamine
Some produce alpha-2 receptor blockade
Which SSRI’s work only on serotonin?
Fluoxetine (prozac), sertraline (zoloft), paroxatine (paxil), fluvoxamine (luvox), escitalopram (lexapro)
Note: Prozac has the longest half-life
Which Atypical SSRIs work on serotonin and norepi?
Bupropion (wellbutrin), trazadone (desyrel), nefazodone (serzone), venlafaxine (effexor), duloxetine (cymbalta)
SSRI side effects?
Insomnia, fatigue, agitation, orthostatic hypotension, headache, N/V, sexual dysfunction, increased appetite
Note: SSRIs have a higher index of safety than other antidepressants (minimal BP effects, cardiac conduction, changes in seizure threshold)
Anesthetic Considerations: What do SSRIs do to CP-450 and platelet activity?
INHIBITS CP-450 enzymes which may increase plasma concentration of certain drugs
Antiplatelet activity, increased risk of bleeding
What is serotonin syndrome?
It can be medication induced for patients taking SSRIs
s/s: confusion, fever, shivering, ataxia, diaphoresis, hyperreflexia, muscle rigidity
What are uses and mechanism of action of TCAs (tricyclic antidepressants)?
Uses: depression and chronic pain in lower doses (TCAs have a similar chemical structure to LAs, inhibit overactive inflammatory response)
MOA: blocks reuptake of serotonin and/or NE at presynaptic terminals
What is the MOA of tertiary amines vs secondary amines and name specific drugs?
Tertiary amines- inhibit serotonin and NE reuptake. Amytriptyline (elavil), imipramine (tofranil), and clomipramine (anafranil)
Secondary amines- inhibit NE reuptake. Desipramine (norpramin), nortriptyline (pamelor)
TCA pharmacokinetics? (lipid/water soluble, protein bound or not, E1/2t, metabolize)
Highly lipid soluble, strongly protein bound
LONG e1/2t (10-80 hours).. especially elderly population
Metabolized in liver and has ACTIVE metabolites
TCA side effects?
Anticholinergic- dry mouth, tachycardia, urinary retention, ileus
CV- orthostatic hypotension, tachycardia, depressed conduction
CNS- lower seizure threshold, weakness, fatigue
With overdose, cardiotoxicity, seizure, CNS depressant effects can be fatal
What can happen if someone is taking TCAs and MAOI’s?
CNS toxicity: hyperthermia, seizure, coma
What are drug interactions/considerations for people taking TCAs? (list the class of drugs)
Sympathomimetics, inhaled anesthetics, anticholinergics, antihypertensives, opioids
What is the anesthetic consideration with a patient taking TCAs and giving sympathomimetics?
Unpredictable because it is indirect acting, there will be exaggerated responses due to longer amounts of NE available to receptors
Use low dosages of sympathomimetics (ephedrine) OR use a potent direct acting drug (phenlyephrine will directly effect the receptor to increase BP)
Note: Someone just started TCA will react stronger than someone who has been on TCAs for a long time
What is the anesthetic consideration for patients on TCAs using… volatile anesthetics agents? Opioids? Barbiturates?
Higher mac of volatile anesthetic agents
Decrease dose of opioids
Decrease dose of barbiturates
What is the anesthetic consideration for patients on TCAs using anticholinergics?
More likely to have post op delirium and confusion (central anticholinergic syndrome)
s/s of anticholinergic toxicity or central anticholinergic syndrome- flushing, dry mouth and skin, mydriasis
Note: Use glycopyrrolate instead of atropine because atropine crosses BBB
What are s/s of TCA overdose? What will they die from?
s/s- agitation, excitement/delirium, progresses to coma, respiratory depression, and cardiac dysrhythmias and sudden death, hypotensive, anticholinergic effects
With TCA will die from myocardial depression or ventricular dysrhythmias
What inactivates MAO enzyme system?
Dopamine, epinephrine, norepinephrine, and serotonin inactivate MAOs
Note: MAOs found in the outer mitochondrial membranes
MAOI (monoamine oxidase inhibitors) mechanism of action?
Blocks the enzyme that metabolizes biogenic amines, forms a stable irreversible complex with MAO enzyme (breaks down amine) which increases amount of neurotransmitter available in the brain/CNS and peripheral nervous system
Why aren’t MAOIs used often?
Side effects
Lethal in overdose
Difficult dosing
Tyramine free diet
List MAOIs
Phenelzine (nardil)
Tranylcypromine (parnate)
Isocarboxaxid (marplan)
Selegiline (eldepryl) - also used for parkinson’s