[PHARMA] LOCAL ANESTHETICS

Question 1

Local anesthetic definition

Answer 1

a drug that induces reversible loss of sensation without inducing loss consciousness or sleep

Question 2

esters example

Answer 2

procaine

Question 3

short acting LA

Answer 3

procaine (0.5-1h)

Question 4

intermediate acting LA

Answer 4

lidocaine (2h)

Question 5

long acting LA

Answer 5

bupivacaine (3h)

Question 6

esters are hydrolyzed by

Answer 6

plasma pseudocholine esterases

Question 7

amide are metabolized by

Answer 7

liver

Question 8

PABA derivatives & liable to allergy

Answer 8

ester LA

Question 9

liable to induce systemic toxicity

Answer 9

amide LA

Question 10

amides duration of action is prolonged in case of

Answer 10

liver disease
reduced hepatic BF as in heart disease

Question 11

esters duration of action

Answer 11

short

Question 12

amides duration of action

Answer 12

long

Question 13

duration of action is prolonged in esters by

Answer 13

genetic plasma pseudo choline esterase deficiency

Question 14

LA mechanism of action

Answer 14

bind to receptors on inner surface of Na channel & block them=>block action potential

Question 15

neurons sensitive to LA

Answer 15

Small neurons (pain,temp, autonomic nerves)
rapid firing nerves (sensory nerves)

Question 16

motor neurons are only affected by LA in case of

Answer 16

higher LA concentration

Question 17

pKA of LA

Answer 17

7.7-9

Question 18

pH of LA is

Answer 18

basic, they’re weak bases

Question 19

LA solubility can be increased by

Answer 19

preparing them as acid salts

Question 20

forms of LA

Answer 20

ionized
unionized

Question 21

which form of LA can cross nerve membrane

Answer 21

unionized

Question 22

relation between PPB and LA

Answer 22

proportional

Question 23

LA with highest percentage of PPB and therefore longer duration of action

Answer 23

Bupivacaine (95%)

Question 24

relationship between lipid solubility and potency

Answer 24

proportional

Question 25

lipid solubility affects

Answer 25

potency

Question 26

the more the lipid content the ____the potency

Answer 26

potency

Question 27

pKa affects

Answer 27

speed of onset

Question 28

the lower the pKA the ____the onset of action

Answer 28

faster

Question 29

affect of pKa

Answer 29

the lower the pKa the more unionized forms there is= faster onset

Question 30

lidocaine pKa

Answer 30

7.9

Question 31

bupivacaine pKa

Answer 31

8.1

Question 32

which drug has a higher percentage of unionized forms: Lidocaine or Bupivacaine

Answer 32

Lidocaine

Question 33

affect of extracellular pH

Answer 33

the more acidic the ECF pH, the less the unionized forms available= less crossing=less anesthesia

Question 34

factors increasing extracellular acidity

Answer 34

infections or lidocaine Hcl repeated injection

Question 35

how can extracellular acidity be decreased

Answer 35

adding NaHCO3

Question 36

affect of vasoconstrictors

Answer 36

prolong action of LA decrease absorption--> ↑duration & ↓systemic toxicity

Question 37

LAs affect on BV

Answer 37

induce VD-->↑ absorption--> termination of effect-->↑risk of toxicity

Question 38

adverse effects & toxicity

Answer 38

~CNS= -sleepiness, numbness, metallic taste (low) -tremors, convulsions, resp depression, coma,death (high conc) ~Neurotoxicity ~CVS: HypoTN, Bradycardia ~allergy (esters) ~↑BP & arrhythmias with VC added to LA

Question 39

neurotoxicity can happen due to

Answer 39

high conc of LA injected close to nerve trunk/spinal cord

Question 40

side effect of high dose Bupivacaine

Answer 40

extremely cardiotoxic

Question 41

drug interaction b/w LA x propanolol

Answer 41

↓hepatic BF= impairs lidocaine clearance= toxicity

Question 42

drug interaction b/w LA x adrenaline x Propanolol

Answer 42

dangerous rise in BP due to unopposed alpha action

Question 43

drug interaction b/w LA x adrenaline x TCAs

Answer 43

hypertensive crisis

Question 44

DOC in surface anesthesia

Answer 44

lidocaine

Question 45

surface anesthesia is used in

Answer 45

minor surgery

Question 46

infiltration anesthesia is used in

Answer 46

minor surgery

Question 47

nerve block anesthesia is used in

Answer 47

dentistry & surgery

Question 48

spinal anesthesia site of injection

Answer 48

subarachnoid space below L2

Question 49

spinal anesthesia is used in

Answer 49

abdomen surgery pelvis, leg surgery when GA is CI

Question 50

anesthesia injected close to nerve trunks

Answer 50

nerve trunk

Question 51

anesthesia applied to skin, mucous membranes of nose, mouth, cornea as solution/jelly/cream

Answer 51

surface anesthesia

Question 52

anesthesia injected SC & submucosal to reach nerve branches

Answer 52

infiltration

Question 53

IV regional anesthesia procedure

Answer 53

double cuff is applied & inflated above arterial BP LA is injected after elevation to drain venous the system

Question 54

side effects of spinal aesthesia

Answer 54

headache hypoTN spinal root injury infection

Question 55

hypoTN as a result of spinal anesthesia is due to

Answer 55

sympathetic nerve block

Question 56

headache as a result of spinal anesthesia is due to

Answer 56

CSF leakage & traction

Question 57

CSF leakage & traction in spinal anesthesia can be avoided by

Answer 57

pencil point needles

Question 58

anesthesia injected outside the dura to block the spinal roots

Answer 58

epidural anesthesia

Question 59

epidural anesthesia is used in

Answer 59

painless labor