40 Questions
What is the potential risk associated with para-aminobenzoic acid (PABA) and its derivatives?
Allergic reaction
What is the mechanism by which articaine is metabolised in plasma?
Hydrolysis by pseudocholinesterase enzyme
What is the primary adverse effect associated with bupivacaine?
Cardiotoxicity
What is the primary route of elimination for unchanged local anaesthetics?
Renal clearance
What is the mechanism by which prilocaine is metabolised?
Aromatic ring metabolism
What is the primary mechanism by which local anaesthetics prevent or relieve pain?
By inhibiting the influx of sodium (Na+) ions through voltage-gated Na+ channels
What is the primary factor that determines the effectiveness of local anaesthetics?
Lipid solubility
What is the primary reason why procaine (novocaine) is no longer widely used as a local anaesthetic?
It is less effective than other local anaesthetics
What is the primary purpose of additives in local anaesthetics?
To enhance the efficacy of the anaesthetic
What is the primary consequence of ineffective pain management in dental practice?
Increased anxiety about dentistry
What is the primary mechanism of action of local anaesthetics on the peripheral nervous system?
Blocking the conduction of nerve impulses by interfering with Na+ channels
Which of the following is a symptom of an allergic reaction to amide local anaesthetics?
Lip swelling and periorbital oedema
What is the half-life of lignocaine in the body?
2 hours
What is the primary site of biotransformation of lignocaine?
Liver
What is the most common local anaesthetic used in dentistry?
Lidocaine
What is the primary mechanism by which local anesthetics work?
By blocking the sodium channels in nerve cells
What is the primary advantage of using prilocaine over lidocaine?
It has a lower risk of methemoglobinemia
What is a common complication of using articaine?
Permanent sensation loss
What is the maximum safe dose of lidocaine?
500mg
What is the primary concern when using bupivacaine?
Cardiac toxicity
What is the rare complication associated with benzocaine and lidocaine topical use?
Allergic reactions
What is the primary advantage of benzocaine and lidocaine topical anaesthetics?
Poor lipid solubility and absorption into the systemic system
What is the peak duration of benzocaine and lidocaine topical anaesthetics?
5 minutes
Which of the following topical anaesthetics is suitable for children above 5 months?
Bonjela Junior Gel
What is the ingredient in Bonjela Junior Gel that serves as an antiseptic?
Cetylpyridinium Chloride
What is the primary reason for reduced potency of local anaesthetics in inflamed tissue?
Increased H+ ions in the tissue
What determines the equilibrium between the lipid-soluble base (B) and the ionized form (BH+) of a local anaesthetic?
pH of the tissue
Why do local anaesthetics with lower pKa values have a more rapid onset of action?
They have lower ionisation at a given pH
What is the consequence of greater lipid solubility of local anaesthetics?
Increased potency and duration, but also increased toxicity
What is the effect of a higher pKa value on the onset of action of a local anaesthetic?
Slower onset of action
What is the unique property of cocaine that makes it different from other local anaesthetics?
It causes vasoconstriction by inhibiting noradrenaline re-uptake
What is the primary difference between amino esters and amino amides?
Amino esters are broken down by cholinesterase enzymes, while amino amides are broken down by liver enzymes
What is the primary reason why local anaesthetics are used via local injection or topical application, but not ingested or used systemically?
To target the specific area of pain
What is the primary mechanism by which local anaesthetics prevent pain?
By blocking the transmission of pain signals to the brain
What is the primary advantage of using a vasoconstrictor with a local anaesthetic?
It decreases the systemic absorption of the local anaesthetic
What is the primary difference between procaine and tetracaine?
Procaine has a short duration, while tetracaine has a long duration
What is the primary reason why local anaesthetics are used in dental procedures?
To prevent pain during the procedure
What is the primary mechanism by which amino esters are broken down?
By cholinesterase enzymes in the extracellular fluid
What is the primary advantage of using local anaesthetics with a shorter half-life?
They are less toxic
What is the primary purpose of understanding pain pathways and action potentials in the context of local anaesthetics?
To understand the mechanism of action of local anaesthetics
This quiz covers the effect of local anesthetics on nerve fibers, including the differential sensitivity of nerve fibers and the order in which sensations are lost. Learn about the effects of LA on pain transmission and more.
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