Unit 4: LA pharmokinetics/dynamics

Question 1

average pKa of LA is

Answer 1

8

Question 2

alkalinization _____ the % of lipid-soluble or non-ionized form​

what do you add to do this?

Answer 2

bicarb
- faster onset on action
- enhances depth
- increase spread

Question 3

Answer 3

Acid:
pK AFTER pH

Base:
Pk comes BEFORE the pH

Question 4

if you give precedex with a LA, what happens?

Answer 4

Increased duration of:​

Both motor and sensory blocks​

First analgesic request after spinal anesthesia​

Question 5

if you give mag with LA, what happens to the duration?

Answer 5

Increased duration with SAB /c or /s opioids.​

Question 6

Clonidine and ketamine given with LA will ___ duration o fLA

Answer 6

prolong

Question 7

Dexamethasone given with LA will ____ duration of LA

Answer 7

prolong

Question 8

What 2 LA combined can produce tachyphylaxis

Answer 8

Chloroprocaine & Bupivacaine​

if you give too much bicarb in the mix the drug will precipitate

Question 9

why do we use vasoconstrictors with LA?

Answer 9

The duration of action of a LA is proportional to the time the drug is in contact with nerve fibers.​

Increased neuronal uptake of LA​

α-adrenergic effects may have some degree of analgesia​

No effect on onset rate of LA​

Enhanced cardiac irritability with inhaled anesthetics​

Systemic absorption  HTN (~ tachycardia?)​

Question 10

1:200,000 is what concentration?

Answer 10

5mcg/ml

Question 11

1:500,000 is what concentration?

Answer 11

2mcg/ml
“how many 500,000 are in a million?”

Question 12

usually dose of vasoconstrictor with LA is Epinephrine ___ mg or Phenylephrine ____ mg​

Answer 12

0.2; 2

Question 13

Your surgeon injected 20 mLs of Bupivacaine 0.25% with 1:200,000 of Epi. ​

What are the total mgs for Bupivacaine and the total mcgs for Epinephrine?​

​

Answer 13

2.5mg/ml bup
2.5 X 20ml = 50mg total

5mcg/ml epi
5mcg X 20ml = 100mcg