Types of anaesthetic

Question 1

Lignocaine -

Answer 1

renders nervous tissue unable to transmit an impulse on stimulation

Question 2

Lignocaine is

Answer 2

widely used, fast acting + lasts from 1.5 to 2 hours

• usually supplied in 2% solution with vasoconstrictor adrenaline in a 2ml cartridge
• maximum dose is 15ml if contains a vasoconstrictor

Question 3

Lignocaine contraindications

Answer 3

most ill effects from LA result from accidental trans-vascular injection

• lignocaine circulating in blood have an effect on heart as it is a cardiac depressant, resulting in slowing impulses to the heart
• care taken with pt who has suffered cardiac infarction or those on drugs to stabilise the heart.

Question 4

Articaine

Answer 4

widely used in UK for non complex routine dental trts; in dose of 4% articaine (1:100,000 epinephrine)

Question 5

Articaine is more likely

Answer 5

-to achieve anaesthetic success in posterior first molar area with low risk factor. not to be used in children under 4

Question 6

However, articaine

Answer 6

injections are thought to have a higher pain score at injection site after anaesthetic reversal

Question 7

Adrenaline

Answer 7

now synthetically produced + frequently supplied in LA cartridges at a concentration of 1 part adrenaline to 80,000 parts local solution. it has normal shelf life of two years

Question 8

Intra-vascular injection of adrenaline

Answer 8

will cause dilation of blood vessels in skeletal muscles + myocardium, this may cause pt to complain of palpitations

Question 9

Prilocaine

Answer 9

effective but 60% less toxic than lignocaine, also supplied in 2ml cartridges with the vasoconstrictor fellypressin, or without
the maximum dosage recommended is with 3% felypressin is 10ml

Question 10

Felypressin

Answer 10

synthetic vasoconstrictor usually supplied with 3% priolocaine.
0.03 international units of felypressin per ml of prilocaine
this is equivalent of 1:2000,000

Question 11

Felypressin also

Answer 11

exerts only vasoconstrictor action + has no adrenaline affect on the heart
should not be used for pregnant pts as it had a mild oxytoxic effect which may impede placental circulation by interfering with the tone of the foetus

Question 12

Vasoconstrictors

Answer 12

usually added to anaesthetic solutions to slow blood circulation in the locality of infected tissue
-this delays the removal of anaesthetic as the vasoconstrictor delays absorption into the blood stream + risk of generalised poisoning is reduced