004 - Injectable anesthetics Flashcards
Barbiturates are weak acids or bases?
acids
Barbiturates inhibit what tissues?
Nerve, heart, smooth muscle, skeletal muscle
in order of greatest to least
Barbiturates (injectable anesthetic) with the Highest lipid solubility:
Ultra-short-acting
Barbiturates (injectable anesthetic) with the Lowest partition coefficient
Long-acting
Barbiturates (injectable anesthetic) with the Highest plasma protein binding
Ultrashort-acting
Barbiturates (injectable anesthetic) that is the best displacer of other drugs, increasing their action?
Ultrashort-acting
Excretion contributes to duration of action for this Barbiturate (injectable anesthetic)?
Long-acting
Redistribution determines duration of action for this Barbiturate (injectable anesthetic)?
Ultrashort-acting
epeated doses of which increases their duration for this Barbiturate (injectable anesthetic)?
Ultrashort-acting
What do repeated doses of ketamine do to duration of action or change in efficacy?
Decrease their efficacy (can gain tolerance i.e. “tachyphlaxis.” After a while, animal no longer anesthesized at same dose)
To enhance the excretion of phenobarbitol, what would you use?
Alkylinize Urine
Causes tolerance due to induction of liver enzymes?
Phenobarbitol (in liver, pharmo-kinetic tolerance
Which has the greatest changes produced to tolerance acceptance produced in the brain (ultra-short, short or long acting barbiturates)?
Ultrashort-acting (pharmaco-dynamic;in brain. ultra short acting best at this.)
At anesthetic doses barbiturates inhibit what body drive?
Barbiturates at Anesthetic Doses Inhibit Sensitivity to PCO2 (resp drive)
What gas are you less sensitive to at a lethal dose of Barbiturates (in regards to respiration)?
Barbiturates at Lethal Doses Cause The Body to be Least Sensitive to PO2 (body reaction is less sensitive to)
Anesthetics that cause excitation in greatest amount of species
Ketamine
Which has more of a respiratory depressant (ketamine or pentabarb)?
Pentabarb
Of the two, ketamine or pentabarb, which one is more likely to cause apnea after an i.v. injection?
Pentabarb (any type of an a barbituate will have more resp depression than ketamine)
Produce most salivation; ketamine or pentabarb?
Ketamine (propofol)
Most skeletal muscle relaxation (ketamine or pentabarb)?
Pentobarbital
Most analgesia (ketamine or pentabarb)?
Ketamin (barbs have no analgesia at all)
Most spares muscle tone (ketamine or pentabarb)?
Ketamine
Affect of ketmaine on bp
increase (animal could bleed out if trauma)
affect of pentabarb on bp
Pentabarb reduces blood pressure
Withdrawal of which barbiturate can cause a seizure (long, short, ultra-short)?
All 3
especially ultra short acting
(ultra-short have greatest effect in brain)
(long acting have biggest effect in liver)
What condition/s might an animal have that might require you to increase the dose of pentabarbitol?
Epileptic condition or ongoing seizure
What does barbiturates have on the g.i. tract during and after surgery (same, different, etc)?
- Decrease in motility during surgery (smooth muscle relaxation all along the gut, you get a stasis)
- increase in motility after surgery (spasms, vomitting. Acts like a withdrawal effect)
a continuous i.v. infusion/drip of _____ would cause anesthesia?
Propofol
Which anesthetic compound is most likely to cause hallucinations?
Ketamine
Which anesthetic compound is most likely to cause a burning sensation when injected i.m. (but may not cause tissue damage)?
Ketamine
Anesthetic Compound that is Contraindicated in animals with history of seizure?
Ketamine
What do repeated doses of ketamine do to duration of action or change in efficacy?
Decrease their efficacy (can gain tolerance i.e. “tachyphlaxis.” After a while, animal no longer anesthesized at same dose)
Contraindicated in cases of head injury?
Ketamine
Tachyphlaxis develops to which anesthetic compound?
Ketamine
Which is the safest i.v. anesthetic with less of a decrease bp effect (but problem with causing steroid synthesis decrease/adrenal difficiency)?
Etomidate
With inhalant anesthetics, how is the ED50 expressed?
Expressed as MAC value, not ED50
What are the units for the new ED50 value expressed in for inhalant anesthetics?
Given in Volume % (total volume of gas being administered to patient through the machine)
Inhalants have a high/low therapeutic ratio?
Low
What is the general MAC value for anesthetics i.e. what MAC value will most likely cause anesthesia?
In general about 1.5-2x MAC value
The anesthetic potency produced by inhalant gases is caused by what characteristic of a gas?
Oil:Gas partition coefficient (i.e. lipophilic)
Rate of induction and recovery by inhalant gases depends on?
Blood:Gas Partition Coefficient (hydrophilicity of compound since blood is aqueous)
A high lipophilicity gives a gas what characteristic?
Means that Gas will be more potent
A high hydrophilicity gives a gas what characteristic?
Means that the gas will have a slow onset/termination of action (onset/termination mirror each other)
Term for: When one gas helps draw in another?
Second Gas Effect
What gas can you use to draw another gas into the body
Nitrous oxide (also has very mild analgesic property, so could be used for that as well)
Most gases delivered are lost by what route?
Delivered and Expelled through the Lungs
Gases are absorbed in what body tissue the longest?
Adipose tissue (not only inhalant anesthetics. Also true for barbiturates)
If you metabolize a drug, is it highly blood soluble or low solubilty?
Metabolism is associated with a high solubility
The “Most Potent” anesthetics have a high or low MAC value?
Low
Isoflourane is not metabolized because of…..
Its low blood solubility
Isoflourane is especially useful for what type of patients?
Birds
History of seizures
Critically ill
Sevoflourine is metabolized, but not toxic. Why?
Low tissue solubility (still metabolized, but does not get into tissues)
Methoxyflourane is no longer used due to what problem?
Nephrotoxicity
To what degree is Methoxyflourane metabolized?
High (50%) metabolism
Sevoflourane is unstable (compared to Isoflourene) so it requires…..
A Preservative (Isoflourane is stable without preservatives)
Sevoflourane produces what effect better than some of the other compounds?
Skeletal Muscle Relaxation
but not very potent across the board for other effects
Isoflourane and Sevoflourane have a unique effect on animals that have a genetic trait that will lead them to a pathological situation. What is this effect and pathological situation?
Malignant Hyperthermia
Both effect Temperature in the patient
Nitrous Oxide used alone as an anesthetic would require you to……
You would have to have the patient under pressure to allow it to work or it would Decrease the amount of oxygen intake in the patient
If you use Nitrous Oxide and don’t allow the animal to recover gradually, what could happen?
Diffusion Hypoxia (goes in so fast and comes out so fast that it does not allow oxygen to go back through the airways)
Nitrous Oxide used for extended periods (hours) of time would cause what type of pathology?
Accumulation in different pockets of the body Polyneuropathy syndrome (long term and painful nerve damage)
