Topical Anaesthetic Agents Overview
24 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is a common application for benzocaine?

  • Spinal anesthesia
  • Earache treatment (correct)
  • Nerve block anesthesia
  • Root canal anesthesia
  • Which type of local anesthetic is more commonly used due to its stability and low risk of hypersensitivity reactions?

  • Procaine
  • Esters
  • Benzocaine
  • Amides (correct)
  • What is the half-life of lignocaine?

  • 1.5-1.8 hours (correct)
  • 2-3 hours
  • 6-10 minutes
  • 30 minutes
  • Which local anesthetic is least likely to cause an allergic reaction among those listed?

    <p>Lignocaine</p> Signup and view all the answers

    What is a significant risk associated with the use of high concentrations of benzocaine?

    <p>Methemoglobinemia</p> Signup and view all the answers

    Why is procaine generally not preferred for dental procedures?

    <p>All of the above</p> Signup and view all the answers

    Which local anesthetic is likely to be a better choice for someone with pseudocholinesterase deficiency?

    <p>Mepivacaine</p> Signup and view all the answers

    Which characteristic is true for ester local anesthetics?

    <p>Higher risk of allergic reactions</p> Signup and view all the answers

    What is the onset time for Xylocaine 5% Ointment?

    <p>3-5 minutes</p> Signup and view all the answers

    How long does the effect of Xylocaine 5% Ointment typically last?

    <p>15-20 minutes</p> Signup and view all the answers

    Which of the following statements about Oraqix is true?

    <p>It has an onset of action of 30 seconds.</p> Signup and view all the answers

    What is the active ingredients composition of Oraqix?

    <p>Lignocaine 25mg/g and Prilocaine 25mg/g</p> Signup and view all the answers

    What is the safe administration route for Oraqix?

    <p>Applied to the periodontal sulcus</p> Signup and view all the answers

    Which of the following local anesthetics is used without adrenaline?

    <p>Mepivacaine (plain)</p> Signup and view all the answers

    What is a key characteristic of Oraqix regarding its physical properties?

    <p>It is a liquid that gels at body temperature.</p> Signup and view all the answers

    What is a disadvantage of using Xylocaine 5% Ointment?

    <p>It is ineffective on dry mucosa.</p> Signup and view all the answers

    How does the addition of sodium metabisulfite to a local anesthetic affect the solution?

    <p>It prevents oxidation of vasoconstrictors.</p> Signup and view all the answers

    What is the primary reason vasoconstrictors are added to local anesthetics?

    <p>To counteract the effects of vasodilation.</p> Signup and view all the answers

    Which statement about amide local anesthetics is true?

    <p>They exhibit vasodilatory properties.</p> Signup and view all the answers

    What is the effect of lowering the pH in local anesthetic solutions?

    <p>It causes a slower onset of action.</p> Signup and view all the answers

    What role does sodium chloride play in local anesthetic solutions?

    <p>It adjusts the solution to make it isotonic.</p> Signup and view all the answers

    Why might a dentist choose to administer local anesthesia without a vasoconstrictor?

    <p>To allow for faster absorption of the anesthetic.</p> Signup and view all the answers

    What is one significant consequence of the addition of adrenalin to local anesthetic solutions?

    <p>It causes a reduction in the rate of local absorption.</p> Signup and view all the answers

    What is the effect on patient experience when the pH of a local anesthetic solution is unaltered?

    <p>The anesthetic may act more effectively and rapidly.</p> Signup and view all the answers

    Study Notes

    Topical Anaesthetic Agents

    • Topical anaesthetic agents are categorized by their intermediate chains: Esters (one 'i' in the name) and Amides (two 'i's in the name).

    • Esters are less common but are used for topical application in some cases.

    Ester Anaesthetics

    • Procaine (brand name Novocaine) was introduced in 1905.

      • Slow onset (6-10 minutes) due to high pKa.
      • Short duration (60 minutes) due to rapid metabolism by pseudocholinesterase in plasma (98%).
      • High dose (10 mg/kg) is possible due to short half-life.
      • Vasodilating properties.
      • Hypersensitivity reactions to inactive metabolite para-aminobenzoate (PABA) are a common problem.
      • Pseudocholinesterase deficiency (affecting 1 in 2800-3000 people) can lead to abnormally slow metabolism and risk of methemoglobinemia.
    • Benzocaine is used for topical application.

      • Found in sore throat lozenges, mouthwash, throat spray, gel, and paste.
      • Can also be used for earache and sunburn.
      • Overuse of high concentrations can cause methemoglobinemia.

    Amide Anaesthetics (Most Common in Dentistry)

    • Lignocaine

      • 2% plain or with adrenaline (27.5 mcg).
      • Half-life of 1.5-1.8 hours.
      • Lignospan Special is another brand name.
    • Articaine

      • 4%.
      • 1:100,000 adrenaline.
      • Half-life of 1.8 hours (slight longer than Lignocaine).
      • Septanest is another brand name.
    • Prilocaine

      • 2.2ml or 1.8ml cartridges.
      • 3% with or without felypressin (vasoconstrictor).
      • Half-life is similar to Lignocaine.
      • Citanest is another brand name.
    • Oraqix

      • Gel containing Lignocaine (25mg/g) and Prilocaine (25mg/g).
      • Applied to periodontal sulcus prior to scaling/cleaning for 30-second onset.
      • Duration of action is 17-20 minutes.

    Factors Affecting Local Anaesthetic Efficacy

    • pH is a critical factor influencing the burning sensation of local anaesthetics.

    Common Additives to Local Anaesthetic Solutions

    • Antioxidants (commonly sodium metabisulfite)

      • Protects vasoconstrictor from oxidation.
      • Lowers pH, leading to slower onset and increased burning during injection.
    • Sodium Chloride

      • Used to adjust the solution to become isotonic.

    Vasoconstrictors

    • All amide local anaesthetics are vasodilators.
    • Vasoconstrictors are added to counter vasoconstriction.
      • Slow local absorption of the drug, increasing duration of action and reducing toxicity.

    Topical Anaesthetic Applications in Dentistry

    • 5% Lignocaine Ointment
      • Adheres to dry mucosa.
      • Onset of action in 3-5 minutes.
      • Duration of action of 15-20 minutes.
      • Does not work on intact skin.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    W7 Local Anaesthesia Agents PDF

    Description

    Explore the classification and characteristics of topical anaesthetic agents, focusing on Esters and Amides. Learn about Procaine and Benzocaine, their properties, uses, and associated risks. This quiz is essential for understanding the implications of these agents in medical applications.

    More Like This

    Understanding Topical Anesthetics
    17 questions

    Understanding Topical Anesthetics

    LightHeartedMaxwell4864 avatar
    LightHeartedMaxwell4864
    Dentistry Chapter 37 Flashcards
    7 questions

    Dentistry Chapter 37 Flashcards

    RevolutionaryDulcimer avatar
    RevolutionaryDulcimer
    RDA Review Practice Test Flashcards
    99 questions
    NC Dental U Final Exam Flashcards
    30 questions

    NC Dental U Final Exam Flashcards

    ImprovingSocialRealism4496 avatar
    ImprovingSocialRealism4496
    Use Quizgecko on...
    Browser
    Browser