CNS Drugs 2

Question 1

Describe the differences between anesthesia and analgesia

Answer 1

Analgesia is reduced pain w/ or w/out sedation. Anesthesia is a degree of loss of touch and temperature senses.

Question 2

How does epinephrine prolong the duration of action of local anesthetics? Hint: also decreases toxicity & local bleeding

Answer 2

alpha1 stimulation–> vasoconstricts blood vessels at site of administration, slows absorption of local anesthetic away finto systemic circulation

Question 3

Epinephrine alpha stimulation causes vasoconstriction. How does this affect local anesthetics?

Answer 3

Slows absorption away from site of administration into systemic circulation; increases duration, lessens toxicity & local bleeding

Question 4

What is the MOA of ALL local anesthetics?

Answer 4

reversibly block Na+ influx, prevent peripheral n. depolarization (no AP), cause loss of sensation in area supplied nerve

Question 5

Differentiate amide-type and ester-type anesthetics:
mepivacaine
etidocaine
bupivacaine+
lidocaine+
articaine
proparacaine
tetracaine
benoxinate
cocaine

Answer 5

Amide: have 2 i’s; (last 4 are esters) Amides are metabolized in liver by CYP 450 enzymes, typically injectable, & longer duration, more toxic; Esters are metabolized by blood plasma esterases, common topical eyedrops, shorter duration, more allergic reactions (1 i in generic name)

Question 6

Which 3 CNS drugs are Schedule IV (4) substances?

Answer 6

tramadol, propoxyphene, benzos

Question 7

Which 2 CNS drugs are Schedule III (3) substances?

Answer 7

<91 mg codeine and buprenorphine

Question 8

Which CNS drugs are Schedule II (2) substances?

List 9

Answer 8

morphine, fentanyl, meperidine, hydromorphone, oxycodone, methadone, hydrocodone, >90mg codeine, ADHD meds

Question 9

Distinguish between the ascending and descending pathways.

Answer 9

Ascending- transmits pain to brain; descending- inhibits ascending pathway

Question 10

Why are local anesthetics not as effective when tissue is very inflamed and require increased doses?

Answer 10

Ionized fraction of drug increases because pH is lower (acidic) in inflamed tissue, non-ionized is needed to cross cell membrane