Local Anaesthetics

What is the mechanism for Local Anaesthetics?

Which pathway carries pain and temperature information?

How is the strength of a pain signal encoded?

What determines how easily a LA blocks the transmission of an AP?

What type of information is carried in a:
1) Aa
2)Ab
3)Ad
4) C

Which of the four classes of nerve fibres isn't myelinated?

What is the order of size of nerve fibres? (LARGEST TO SMALLEST)

Which nerve fibres are most sensitive to block by LAs

Describe the 3 main parts of a LA

Describe the structure of an Ester

Describe the structure of an Amide

What determines the percentage of an LA which is ionised?

What do pH and pKa equate to?

When does pKa = pH
(or Ka = [H+])

What happens to the percentage of ionised LA as the pH decreases (becomes more acidic)?

HENDERSON-HASSLEBATCH EQUATION

What happens to the acidity of an inflamed tissue?

What are the two pathways LAs can take to block sodium channels?

Which pathway is most prevalent?

Describe the Hydrophobic (Lipophilic) pathway.

Describe the Hydrophilic pathway

Where do LAs bind in sodium channels?

Which states do LAH+ have high affinity for?

Why don't LAs affect normal channel APs?

What is the pKa of procaine?

Why is procain hardly used?

What is the pKa of Lidocain (Lignocaine)

What is the plasma half life of lidocaine?

How is lidocaine removed from the system?

What is the time taken for onset?

What can be injected to prolong the effect of LAs?
Give two examples of this

Why do vasoconstrictors prolong the action of LAs?

Give an example of two other LAs containing an ester group

Give an example of another two LAs containing an amide group

What are the two Atypical LAs? (NUMBER 1)

NUMBER 2

Why is benzocaine an Atypical LA?

Why is QX-314 an Atypical LA?

Which LAs are used as surface anaesthetics and in what form?

What is infiltration anaesthesia used for? (And which LAs?)

What is intravenous regional anaesthesia used for? And which LAs are used?

What is nerve-block anaesthesia used for? Where is it injected?

Where is a spinal anaesthesia injected? What is it used for and which LAs are used?

Where is an epidural injected? What is it used for? Which LAs are injected?

How would you treat neuropathic pain?

What are the 3 Adverse effects of LAs?
*NUMBER 1

*NUMBER 2

*NUMBER 3

What are the other clinical uses of LAs?