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Pharm 1 - Injectable Anesthetics

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isabellepjk's version from 2017-05-06 22:21

Basics

Question Answer
What are the 5 classes in injectables?Barbiturates
Dissociatives
Propofol
Neuropeptides
Etomidate/Medetomidate
(NO BENZOS HERE)
Speed of induction is based on what two main things (& examples)?(1) Drug characteristics (lipid solubility, size, protein binding, ionization)
(2) Patient factors (acid/base status, PP conc, CO)
*What are the receptors the 5 classes work on?All of them are GABA agonists EXCEPT Dissociatives, those are NMDA antagonists
What are the three main uses of injectable anesthetics?Induction, maintenance, & TIVA (total intravenous anesthesia)
*What is the class of Injectable anesthetics which provides analgesia?Dissociatives (maybe Neurosteroids?)
Advantages of injectables? (7)(1) Rapid control of airway (prevent aspiration)
(2) Upper airway exam/sx
(3) Rapid control & reduction in CNS activity
(4) Less stressful (TIVA-total intravenous anesthesia)
(5) Better recoveries (TIVA)
(6) CV stability
(7) Improved stability of cerebral autoreg
Disadvantages of injectables? (4)(1) Lg vol distribution
(2) Recovery has redistribution & metabolism to contend with
(3) More difficult to regulate anesthetic depth (Propofol & remifentanyl are easier to tho, bc short 1/2 life)
(4) Potential for human abuse
How do Injectable anesthetics affect the heart?<3 Stability
*What do Injectable anesthetics do to the bronchi? Blood vessels?Dilate
What is the associated benefit of the effect of Injectable anesthetics on the bronchi?Dilate, so rarely need to intubate, & you can do work on the upper airway (barbs might cause laryngeal spasm tho)
*Which drugs are hard to regulate? Easy to regulate?Most are hard to regulate, BUT propafol & remifentanyl are easy to
What does a high protein binding do to the volume of distribution?LOWERS it (stays stuck on proteins, so cant be active)
How do the drugs which work on GABA do their effects?Leave the GABA channel open LONGER (barbs) bc they DECREASE the disassociation rate (Propofol) (more Cl- gets through)
*Which class(s) is not safe for use in head trauma?Dissociatives
*Heart-friendly anesthetics?Dissociatives are best, & Etomidate has minimal effects (safe for congestive heart failure) (Ed makes my heart happy)
Which classes provide mm relaxation?Barbiturates (minus the laryngeal spasms),
Propofol is really good (Warning: Decreases laryngeal reflexes means aspiration risk),
Neurosteroids
*Which classes do not provide mm relaxation?Dissociatives, Etomidate (cant relax if you have ed)
*What are the respiratory friendly classes?Neurosteroids are the best, Etomidate only minimal effects, Dissociatives have resp slightly reduced but not the best of these (Breathe, NED! breathe!)
*Which Barbiturate is commonly used as an anticonvulsant?Phenobarbital
*Which drug is used as euthanasia?Pentobarbital (Put you down in hell w/ the pentogram)
Which has high plasma protein binding? Low?High = Etomidate. Low = Neurosteroids (you EaT a HIGH amount of PROTEINS, you can take a LOW amount of STEROIDS)
memorize

Barbiturates

Question Answer
What are the two kinds of Barbiturates?Thiobarbituates & Oxybarbituates
*What are the Thiobarbituates?Thiopental , Thiamylal
*What are the Oxybarbiturates?Phenobarbital
Pentobarbital
Methohexital
Do Barbiturates provide analgesia?No
Where are Barbiturates metabolized? Excreted?Liver, kidney
What happens to metabolism if the dog is fat? Skinny?BOTH take longer to metabolize.
Fat= lipophilic drug stays in fat & there is redistribution.
Skinny= drug doesn't leave blood because there's no fat to go into, so keeps getting back to brain)
*How do Barbiturates affect the resp system?RESP DEPRESSION!! Also LARYNGEAL SPASMS which means you can't intubate
*Do Barbiturates affect pregnancy?Yes, crosses placental barrier, can cause baby to not take first breath
*What is the shortest acting Barbiturate?Methohexital
Which group lasts longer, the thios or the oxys?Oxys last longer
*Notable about Greyhounds & Barbiturates?Thios last longer in them (lack of enzyme) (Thio's trp on the greyhound laster longer than normal)
*Notable about sighthounds & Barbiturates?Increased effects, they last longer in lean animals! (sIghthounds, Increase, skInny)
*Notable about pigs & Barbiturates?Thiopental lasts longer in the pig bc theyre so fat, therefore, recovery is longer
*Notable about horses & Barbiturates?Flexion in all 4 legs.
Thiopental might cause excitation & incoordination when used alone
Methohexital causes excitation during induction and recovery when used alone.
*What will Barbiturates cause in ruminants?VOMITING, pink tooth (Barbie drank a lot of pink rum and then vomited)
*What is notable about sheep/goats w/ Barbiturates?SUPER FAST degradation of Pentobarbital → 8xs faster
How I'll remember BarbituratesBarb is ok if she gets a concussion, as long as she doesnt stop breathing, because she is pregnant. However, I want to choke her. She does collect cows.
*How do Barbiturates affect cerebral blood flow?Decrease, safe in concussions
memorize

Propofol

Question Answer
Does Propofol provide analgesia?No
How does Propofol affect preg animals?CAN cross the placental barrier, but so short acting that it doesnt really cause clinical consequences
How does Propofol affect the GABA channel?Decreases disassociation rate
What are the indications of Propofol? (5)(1) Induction of general anesthesia
(2) Short term sedation
(3) long term sedation
(4) Maintenance of anesthesia
(5) Treatment of status epilepticus
Which indications of Propofol are provided via CRI (continuous rate infusion)Long term sedation & maintenance of anesthesia
What are the effects of Propofol on intracranial pressure?Decrease - Safe for concussions
*Respiratory effects of Propofol?CAUSES APNEA. Animal might turn purple.
*Effects of Propofol on muscles? Notable muscle group?Muscle relaxation! Suppresses laryngeal reflex!! (Risk of aspiration)
*How does Propofol affect greyhounds?Slower recovery because of a small Vd
*How does Propofol affect old dogs?Slower clearance (old liver & kidney)
Where is Propofol metabolized? Excreted?In the liver & IN THE LUNGS excreted in kidney
*How does Propofol affect cats?Oxidative injuries to RBCs
How well do horses recover from Propofol?Usually a smooth recovery (may show excitement upon induction after sedation w/ an α-2 agonist.)
How does Propofol affect birds?Sig. respiratory depression in red tailed hawks & great horned owls
How I'm gonna remember this shit?MJ is ok if he gets a concussion, as long as he doesnt stop breathing & turn purple, he's so relaxed he can moonwalk amazingly, & although he wont hurt kids (ha) he will hurt cats. He is a majestic owl that will take my breath away.
memorize

Dissociatives

Question Answer
*Receptor action of Dissociatives?NMDA antagonist
Do Dissociatives provide analgesia?YES!
Do Dissociatives provide mm relaxation?No
*How do Dissociatives affect cerebral blood flow?Increase - NO USE IN CONCUSSIONS (when your brain is dissociated, you dont want to dissociate it more)
*How do Dissociatives affect the CV system?GOOD TO USE in HEART PTs! (dissociates heart from the anesthetic affects)
What are the Dissociative drugs?Ketamine & Tileamine
*How do Dissociatives affect cats? (Metabolism-wise)Cat given ketamine will excrete norketamine because they can't glucuronidate
*What is telazol?A 50/50 mix of Tiletamine (Dissociative) & Zolazepam (a Benzodiazepine)
*How does Telazol affect cats & pigs? (Proportion of ingredients effectiveness)Zolazepam > Tiletamine
*How does Telazol affect dogs & horses? (Proportion of the two components)Effects of Tiletamine > Zolazepam (NMDA aka Dissociatives = more pronounced)
(Dogs and Horses have more teeth- t > z)
*How do Dissociatives affect horses?DONT USE AS SINGLE AGENT (no mm relax), & careful w/ Telazol (rough recovery)
*How do Dissociatives affect (large) cats?LARGE CATS AKA TIGERS take DAYS to recover & it might kill them.
*How do Dissociatives affect rabbits?Renal death in ONLY New Zealand white rabbits
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Etomidate/Metomidate

Question Answer
*How does Etomidate affect the CV system?Maintains hemodynamic stability, heart failure friendly
How does Etomidate affect the resp system?Minimal resp effects
Describe the therapeutic index of Etomidate, what does this mean?It’s large, so it's a safer drug
Describe how the molecule of Etomidate affects its function?ONLY THE RIGHT enantiomer is active
Does Etomidate provide analgesia?No
*How does Etomidate affect cerebral blood flow/ IC pressure?Cerebral friendly, safe to use in head trauma
How safe is Etomidate in the long term?DONT USE long term because it reduces cortisol production
Describe the plasma protein binding of Etomidate75% bound
What is the Vd of Etomidate?Large
Describe the recovery of Etomidate in terms of other classesSimilar to Thiopental (a Thiobarbiturate), but slower recovery as compared to Propofol (Propofol leaves system faster than Etomidate)
*How does Etomidate affect cats?Can get clinical hemolysis (causes fragility of RBCs)
*How does Etomidate affect dogs?They can get hemolysis after CRI
*When do you use Metomidate?Anesthetize fishies
Is Etomidate painful?Can cause pain after injection, but this is most likely bc of other components of the injection, not the drug itself
How I'll remember this shitET eats 75% protein powder, takes a deep breath, & can then kill your blood w/ just his right hand
memorize

Neurosteroids

Question Answer
*What is the receptor Neurosteroids work on?GABA
*What are the Neurosteroids (drugs)?Alphaxalone, Alphadolone (people who abuse steroids will soon be allllll alone)
Do Neurosteroids provide analgesia?Maybe
What are the combination drugs of Neurosteroids?Althesin & Saffan
*What animals do you use Neurosteroids on?Cats & dogs
How do you administer Neurosteroids?IM or IV
*How do Neurosteroids affect cerebral blood flow?Decrease, safe to use in head trauma
How do Neurosteroids affect resp fxn?Preserve it :)
How can Neurosteroids cause tissue damage?Perivascular admin will damage tissues
*Do Neurosteroids provide mm relaxation?Yeah, good mm relax
How much do Neurosteroids plasma protein bind?Not extensively at all
*How do Neurosteroids affect cats?Theyre relaxed after 10 seconds
*What happens w/ prolonged use of Neurosteroids?Decrease duration of action (tachyphylaxis?)
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