40 Questions
What is the primary effect of local anaesthetics on nerve conduction?
Inhibiting the influx of sodium ions
What is the main advantage of using local anaesthetics?
Facilitating the delivery of dental care by controlling pain
What is a common problem associated with the use of cocaine as a local anaesthetic?
It has psychogenic effects and is addictive
What is the primary reason for injecting local anaesthetics locally or applying them topically?
To avoid unwanted systemic effects
What is the term for the ability of a local anaesthetic to dissolve in lipids?
Lipid solubility
What is the primary function of additives in local anaesthetics?
To prolong their duration of action
What is the term for the unpleasant sensory and emotional experience associated with actual or potential tissue damage?
Pain
What is the primary purpose of pain management in dental practice?
To facilitate the delivery of care
What is the primary form of the local anaesthetic that penetrates both the tissue and nerve membrane?
Lipid-soluble base (B) form
What happens to the ionic form BH+ in an acidic pH environment?
It reduces the potency of the LA
What is the significance of the pKa value in pharmacology?
It determines the pH at which 50% of the drug is ionised and 50% is present as a base
Why are local anaesthetics less effective in inflamed tissue?
Because the pH of the tissue is more acidic
What is the effect of higher pKa values on the onset of action of local anaesthetics?
Slower onset of action
What is the effect of greater lipid solubility on the potency and duration of local anaesthetics?
It increases the potency and duration
Why do more hydrophobic drugs have a decreased therapeutic index?
Because they are more lipid-soluble
What is the mechanism of action of local anaesthetics in blocking nerve conduction?
By blocking the Na+ channel in the membrane
Which of the following local anaesthetics is naturally occurring and causes vasoconstriction by inhibiting noradrenaline re-uptake?
Cocaine
What is the primary difference between amino ester and amino amide local anaesthetics?
Breakdown mechanism
Which of the following is NOT a common use of local anaesthetics?
Systemic infections
What is the primary mechanism of action of local anaesthetics?
Inhibiting action potentials
Which local anaesthetic is known for its low potency and slow onset of action?
Procaine
What is the primary reason for combining local anaesthetics with vasoconstrictors?
To reduce bleeding at the injection site
Which of the following is an example of an amino ester local anaesthetic?
Procaine
What is the primary reason for understanding pain pathways and action potentials in the context of local anaesthetics?
To understand the mechanism of action of local anaesthetics
What type of nerve fibers are most affected by local anesthetics?
Smaller neuronal alpha-delta (A-δ) fibres
What is the first modality to disappear when local anesthetics are used?
Sensation of pain
What determines the plasma concentration of local anesthetics?
All of the above
What is the elimination half-life of lignocaine in the liver?
2 hours
What is a common symptom of CNS toxicity caused by local anesthetics?
Light-headedness
What is a rare type of allergic reaction to local anesthetics?
Type IV or Type I IgE-mediated immunological reaction
What is a common additive in local anesthetics that may elicit allergic or adverse reactions?
Metabisulphite or parabens
What is commonly used in dentistry to avoid inducing labour in pregnant patients?
Lidocaine
What is the maximum safe dose of lidocaine for a patient?
500mg
What is the pH at which lidocaine is most soluble?
pH 7.7
What is the duration of action of articaine with adrenaline?
2.5 hours
What is the concentration of prilocaine in the forte formulation?
4%
What is the main complication of using high doses of prilocaine?
Methaemoglobinaemia
What is the onset of action of bupivacaine?
Slow onset
What is the concentration of benzocaine in topical anaesthetics?
20%
What is the composition of EMLA cream?
1:1 mixture of lidocaine and prilocaine
Learn about the importance of pain management in dental practice, action potential and pain pathways, and the mechanisms of action of local anaesthetics. This quiz covers the pharmacology of local anaesthesia, specifically designed for Year 1 BDS & DTH students.
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