Drugs Affecting Nerve Excitability

Question 1

Pharmaceutics deals with

Answer 1

Delivery of the drug and with what

Question 2

How do local anaesthetics act?

Answer 2

block depolarising voltage induced Na+ channels by binding to the transmembrane domain S6

Question 3

What does large Vd means (more than plasma)?

Answer 3

high distribution in tissues

Question 4

Local anaesthetics are more active at motor neurons T/F

Answer 4

F, more active at sensory

Question 5

types of local anaesthetics

Answer 5

Aminoesters, aminoamides, benzocaine

Question 6

Aminoesters such as Procaine are ….

Answer 6

Short acting anaesthetics

Question 7

aminoamides such as lignocaine are….

Answer 7

long acting anaesthetics

Question 8

What si the 2 possible mechanisms of action of the anaesthetics? and characteristics

Answer 8

Hydrophilic –> slow acting, use dependent

Lipophilic –> Fast acting, non use dependent

Question 9

Example of lipophilic anaesthetics

Answer 9

Benzocaine

Question 10

Example of hydrophilic anaesthetics

Answer 10

lignocaine and procaine

Question 11

anaesthetics change the membrane potential T/F

Answer 11

F, they just inhibit depolarisation

Question 12

What are the stages of anaesthesia?

Answer 12

Euphoria - Excitement - Anaesthesia - Medullary Depression

Question 13

What is a premedicant?

Answer 13

Depressor of the CNS that erases anterograde memory, used before surgery

Question 14

what are the two targets of antiepileptic medication? give example of the drugs

Answer 14

increase inhibition (benzodiazepines)
Decrease firing (Phenytoin)

Question 15

Mechanism of action of phenytoin

Answer 15

decrease activity of Glutamatergic nerve fibres

Blocks Na+ channels whilst they are open

Question 16

Mechanism of action of benzodiazepines

Answer 16

Increase GABA receptor activity

Question 17

What is the orthostatic site?

Answer 17

the active site

Question 18

what is the allosteric site?

Answer 18

site other than the active site

Question 19

1 Benzodiazepines have large therapeutic windows T/F
2 are used as premedicants T/F
3 highly addictive T/F

Answer 19

T
T
F, not very addictive when compared to barbiturates

Question 20

GABA A receptor is made of how many subunits

Answer 20

5, 3 different types of subunits

Question 21

Benzodiazepines act at what target

Answer 21

GABA A, binding allows for higher frequency of opening to Cl- entry

Question 22

Benzodiazepines bind to which site of the receptor?

Answer 22

Allosteric

Question 23

Diazepam (Benzodiazepine) increases efficacy (ceiling of action) T/F

Answer 23

F, only increases potency and sensitivity

Question 24

Barbiturates have low therapeutic margin T/F

use induces dependence T/F

Answer 24

T

T

Question 25

Barbiturates uses

Answer 25

anticonvulsant and anaesthetic

Question 26

Barbiturates mechanism of action

Answer 26

increases receptor opening time (GABA)

Question 27

Barbiturates modify the efficacy of the receptor T/F

Answer 27

T, increases ceiling of action

Question 28

When is low potency of a drug problematic?

Answer 28

when dose would be too large to administer