MSK: General and Local Anesthetics Flashcards
What is a common suffix of almost all inhaled anesthetics?
-urane
What is the one inhaled anesthetic that doesn’t end in -urane?
Nitrous oxide
How does a high blood:gas coefficient relate to onset of action?
High blood:gas coefficient=more soluble=slower onset
inversely related
How does a low blood:gas coefficient relate to onset of action?
Low blood:gas coefficient=less soluble=faster onset
inversely related
Whats an example of a drug with low blood:gas coefficient therefore quick onset of action?
Nitrous oxide
-very quick, I was out in like 10s when I got my wisdom teeth out
Whats an example of a drug with high blood:gas coefficient therefore slower onset of action?
Halothane
-used for surgeries (not in US; hepatotoxic)
What is the Minimal Alveolar Concentration (MAC) a representation of?
A measure of potency
-the dose at which 50% of subjects have anesthetic effects
Is a higher MAC or lower MAC associated with greater anesthetic effects?
Lower
- if MAC 100%, it would mean pt would need 100% gas to feel it
- if MAC 70%, it would mean pt would only need 70% gas to feel it
What is the most serious adverse effect of halothane?
Hepatotoxicity
-not used much in US; watch for question about pt having surgery in different country
For those inhaled anesthetics that are combined with succinylcholine, what do you need to watch out for and how would you treat?
Malignant hyperthermia
-treat with dantrolene (ryr blocker)
MOA of propofol
GABAa agonist
What is the induction and recovery of propofol?
Rapid onset and rapid recovery
-poor solubility in water
Clinical use of propofol
Can be used for induction and as continuous IV drip for maintenance
Adverse effects of propofol?
CNS depression
Profound vasodilation=hypotension
Respiratory depressant
MOA of etomidate
GABAa receptor agonist
Which anesthetic drug is best for patients with cardiovascular and pulmonary issues?
Etomidate
-causes least amount of CV and pulm depression
What is the induction and recovery of etomidate?
Rapid induction and moderate recovery
Adverse effects of etomidate?
cerebral vasoconstrictor=decrease cerebral blood flow and ICP
Adrenocortical suppression
MOA of ketamine
NMDA receptor antagonist
Adverse effects of ketamine
Dissociated anesthetic
Hallucinations and bad dreams
CNS and CV stimulant
Nystagmus
Which anesthetic causes profound analgesia, stimulation of Sym NS, bronchodilation and has minimal resp depression?
ketamine
MOA of dexadetomide
a2 agonist that causes hypnosis
-works at locus caeruleus with analgesia at level of spinal cord
MOA of midazolam and diazepam?
GABAa receptor agonist
-increase FREQUENCY of opening
-benzos
MOA of fentanyl
μ opiate agonist
Adverse effects of fentanyl and other opiates
CNS and resp depression
constipation
MOA of thiopental and methohexital
GABAa receptor agonist
-increase DURATION of opening
Barbituates
What drug is the antidote to benzodiazepine overdose?
Flumazenil
What drug is often administered before surgery, especially surgeries where patient can keep “sedative” consciousness, ie colonoscopy or spinal surgery?
Midazolam
What type of local anesthetic are:
Lidocaine
Dibucaine
Bupivacine
and Articaine?
Amides
-have two i’s in the name
What type of local anesthetics are:
Benzocaine
Cocaine
Procaine?
Esters
-only one i in name and in in -caine
MOA of the local anestetics?
Block voltage gated sodium channels to prevent spread of action potentials
What fibers are blocked faster by local anesthetics: small or large?
Small
What fibers are blocked faster by local anesthetics: myelinated or unmyelinated?
Myelinated
What fibers are blocked faster by local anesthetics: large myelinated or small unmyelinated?
small unmyelinated
What fiber types are especially sensitive to local anesthetics?
Type A Delta (pain, temp) Type B (preganglionic autonomic) Type C (pain and postganglionic)
What type of drug are local anesthetics often paired with?
Vasoconstrictor (reduces bleeding)
-epinephrine
What are some adverse effects of local anesthetics on CNS?
low doses: headache, light headedness, visual and audio disturbances
High doses: CNS depression and toxicity
What are some adverse effects of local anesthetics on CV system?
Some can block Na conduction in heart, decreasing excitability
-bupivacine is most cardiotoxic
What types of anesthetic are more likely to cause an allergic reaction: esters or amides?
Esters
-if pt has an allergic reaction to ester, switch to amide (lidocaine or other two i)
Which local anesthetic has vasoconstrive properties?
Cocaine
What drug is added with propofol due to injection pain?
Lidocaine or other topical anesthetics
