Pharm 1 - Injectable Anesthetics

martinezdvm's version from 2015-11-01 04:33


Question Answer
What are the 5 classes in injectables?Barbiturates
(Barb is Pro NED)
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 (ED told me NOT TO RELAX)
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 (5 ways to kill Barb)
Which has high plasma protein binding? Low?High = Etomidate. Low = Neurosteroids (you ET proteins, the steroids do the opposite of what you think)


Question Answer
What are the two kinds of Barbiturates?Thiobarbituates & Oxybarbituates
What are the Thiobarbituates?Thiopental , Thiamylal
What are the Oxybarbiturates?Phenobarbital
Do Barbiturates provide analgesia?No
Where are Barbiturates metabolized? Excreted?Liver, kidney
What happens to metabolism if the dog is fat? Skinny?BOTH are LONGER. (Fat= lipophilic drug stays in fat & theres redistribution. Skinny= drug doesnt leave blood bc no fat to go into, so keeps getting back to brain)
How do Barbiturates affect the resp system?RESP DEPRESSION!! Also LARYNGEAL SPASMS which mean 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) (pigs= fat. Greyhounds=no enzyme)
Notable about sighthounds & Barbiturates?Exaggerates effects, they last longer in lean animals!
Notable about pigs & Barbiturates?Thiopental lasts longer in the pig bc theyre so fat (THIOOOOOOOO is a pig)
Notable about horses & Barbiturates?Flexion in all 4 legs. Thiopental might cause excitation & incoordination when used alone. (baaaaad)
What will Barbiturates cause in ruminants?VOMITING, pink tooth (barb brings the feminine touch to rumis w/ pink-- & bulimia)
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


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 so 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
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.


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 A STILL-ACTIVE compound, norketamine, which is 10-30% active. This is bc they can't glucoronidate
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 (benzo aka GABA= more pronounced) (when I'm in front of my PC, I'm relaxed)
How does Telazol affect dogs & horses? (Proportion of the two components)Tiletamine > Zolazepam (NMDA aka Dissociatives = more pronounced) (when I'm in front of my HDtv, I'm asleep)
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. (No Kellogg’s for this tiger)
How do Dissociatives affect rabbits?Renal death in ONLY New Zealand white rabbits (Alice in wonderland trippin on K & sees the white rabbit)


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


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 (ironic that a steroid could cause relaxation-- also ironic that it doesnt care about PP binding)
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?)