40 Questions
What is the primary mechanism of action of cocaine as a vasoconstrictor?
Inhibiting noradrenaline re-uptake
What is the main difference between amino esters and amino amides?
Their breakdown site
Which of the following is NOT a use of local anaesthetics?
Ingestion for pain relief
What is the reason why local anaesthetics are often combined with vasoconstrictors?
To reduce bleeding at the site of injection
What is the main difference between procaine and tetracaine?
Their duration of action
Which of the following is a characteristic of amino esters?
Broken down by cholinesterase enzymes in the extracellular fluid
What is the role of cholinesterase enzymes in the breakdown of local anaesthetics?
Breaking down amino esters
Why is it necessary to understand pain pathways and action potentials to understand the mechanisms of action of local anaesthetics?
Because local anaesthetics act on the pain pathways
What is the primary mechanism of metabolization of some local anesthetics in the plasma?
Hydrolysis by pseudocholinesterase enzyme
Which local anesthetic is known to cause methaemoglobinemia due to its metabolism?
Prilocaine
What is the primary function of nociceptors in the body?
Detection of noxious stimuli
Which of the following local anesthetics is known to produce profound anesthesia and is substantially more cardiotoxic?
Bupivacaine
What is the primary mechanism of action of local anesthetics on voltage-gated sodium channels?
Binding to the channel from the inside
What is the primary difference between lidocaine and prilocaine?
Vasodilation properties
What is the primary advantage of articaine over other local anesthetics?
Greater lipid solubility and diffusion
What is the primary role of the cytosol in the mechanism of action of local anesthetics?
Binding site for local anesthetics
What is the maximum safe dose of lidocaine in a dental formulation?
500mg
Which local anaesthetic has the shortest duration of action?
Mepivacaine
What is the primary complication of high doses of prilocaine?
Methamoglobinaemia
What is the primary use of bupivacaine in dentistry?
Epidurals
What is the lipid solubility of articaine?
pKa 7.8
Which local anaesthetic has the highest potency?
Bupivacaine
What is the maximum safe dose of articaine in a dental formulation?
Not specified
What is the form of the local anaesthetic necessary for penetration of both tissue and nerve membranes?
B
What is the primary use of benzocaine in dentistry?
Topical anaesthesia
What happens to the LA when it enters the nerve axon?
It binds to the inactivation site of the Na+ channel
What determines the equilibrium between BH+ and B?
The pH of the tissues and the pKa of the anaesthetic
What is the effect of an acidic pH on LA potency?
It reduces the potency of LAs
What is the significance of pKa in pharmacology?
It is the pH at which 50% of the drug is ionised and 50% is present as a base
What is the effect of a higher pKa on the onset of anaesthetic action?
It decreases the speed of onset
What is the effect of greater lipid solubility on anaesthetic potency?
It increases both the potency and duration of anaesthetics
What is the drawback of greater lipid solubility?
It decreases the therapeutic index
What is the onset of action of benzocaine and lidocaine topical anaesthetics?
Approx. 1-2 minutes
What is the duration of action of benzocaine and lidocaine topical anaesthetics?
Approx. 15 minutes
What is the peak effect of benzocaine and lidocaine topical anaesthetics?
At 5 minutes
What is the depth of penetration of benzocaine and lidocaine topical anaesthetics?
Approx. 2-3mm
What is the lipid solubility of benzocaine and lidocaine topical anaesthetics?
Poor
Which of the following is NOT a complication of benzocaine and lidocaine topical anaesthetics?
Increased heart rate
What is the active ingredient in Bonjela Adult Gel that provides pain relief?
Choline Salicylate
What is the minimum age for using Anbesol?
12 years
Learn about the different types of local anaesthetics, including benzocaine and lidocaine, and their application in dental practice. Understand the techniques of local anaesthesia and potential complications.
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