Pharmacology of Local Anaesthesia for Year 1 BDS & DTH

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What is the primary effect of local anaesthetics on nerve conduction?

Inhibiting the efflux of potassium ions

Inhibiting the influx of sodium ions (correct)

Stimulating the release of acetylcholine

Increasing the release of dopamine

What is the main advantage of using local anaesthetics?

Inducing unconsciousness in patients

Reducing anxiety about medical procedures

Treating chronic pain

Facilitating the delivery of dental care by controlling pain (correct)

What is a common problem associated with the use of cocaine as a local anaesthetic?

It has psychogenic effects and is addictive (correct)

It is too expensive

It causes allergic reactions

It is ineffective for dental procedures

What is the primary reason for injecting local anaesthetics locally or applying them topically?

To avoid unwanted systemic effects Signup and view all the answers

What is the term for the ability of a local anaesthetic to dissolve in lipids?

Lipid solubility Signup and view all the answers

What is the primary function of additives in local anaesthetics?

To prolong their duration of action Signup and view all the answers

What is the term for the unpleasant sensory and emotional experience associated with actual or potential tissue damage?

Pain Signup and view all the answers

What is the primary purpose of pain management in dental practice?

To facilitate the delivery of care Signup and view all the answers

What is the primary form of the local anaesthetic that penetrates both the tissue and nerve membrane?

Lipid-soluble base (B) form Signup and view all the answers

What happens to the ionic form BH+ in an acidic pH environment?

It reduces the potency of the LA Signup and view all the answers

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 Signup and view all the answers

Why are local anaesthetics less effective in inflamed tissue?

Because the pH of the tissue is more acidic Signup and view all the answers

What is the effect of higher pKa values on the onset of action of local anaesthetics?

Slower onset of action Signup and view all the answers

What is the effect of greater lipid solubility on the potency and duration of local anaesthetics?

It increases the potency and duration Signup and view all the answers

Why do more hydrophobic drugs have a decreased therapeutic index?

Because they are more lipid-soluble Signup and view all the answers

What is the mechanism of action of local anaesthetics in blocking nerve conduction?

By blocking the Na+ channel in the membrane Signup and view all the answers

Which of the following local anaesthetics is naturally occurring and causes vasoconstriction by inhibiting noradrenaline re-uptake?

Cocaine Signup and view all the answers

What is the primary difference between amino ester and amino amide local anaesthetics?

Breakdown mechanism Signup and view all the answers

Which of the following is NOT a common use of local anaesthetics?

Systemic infections Signup and view all the answers

What is the primary mechanism of action of local anaesthetics?

Inhibiting action potentials Signup and view all the answers

Which local anaesthetic is known for its low potency and slow onset of action?

Procaine Signup and view all the answers

What is the primary reason for combining local anaesthetics with vasoconstrictors?

To reduce bleeding at the injection site Signup and view all the answers

Which of the following is an example of an amino ester local anaesthetic?

Procaine Signup and view all the answers

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 Signup and view all the answers

What type of nerve fibers are most affected by local anesthetics?

Smaller neuronal alpha-delta (A-δ) fibres Signup and view all the answers

What is the first modality to disappear when local anesthetics are used?

Sensation of pain Signup and view all the answers

What determines the plasma concentration of local anesthetics?

All of the above Signup and view all the answers

What is the elimination half-life of lignocaine in the liver?

2 hours Signup and view all the answers

What is a common symptom of CNS toxicity caused by local anesthetics?

Light-headedness Signup and view all the answers

What is a rare type of allergic reaction to local anesthetics?

Type IV or Type I IgE-mediated immunological reaction Signup and view all the answers

What is a common additive in local anesthetics that may elicit allergic or adverse reactions?

Metabisulphite or parabens Signup and view all the answers

What is commonly used in dentistry to avoid inducing labour in pregnant patients?

Lidocaine Signup and view all the answers

What is the maximum safe dose of lidocaine for a patient?

500mg Signup and view all the answers

What is the pH at which lidocaine is most soluble?

pH 7.7 Signup and view all the answers

What is the duration of action of articaine with adrenaline?

2.5 hours Signup and view all the answers

What is the concentration of prilocaine in the forte formulation?

4% Signup and view all the answers

What is the main complication of using high doses of prilocaine?

Methaemoglobinaemia Signup and view all the answers

What is the onset of action of bupivacaine?

Slow onset Signup and view all the answers

What is the concentration of benzocaine in topical anaesthetics?

20% Signup and view all the answers

What is the composition of EMLA cream?

1:1 mixture of lidocaine and prilocaine Signup and view all the answers