Chapter 6 Flashcards
(13 cards)
Topical Anesthetic
Anesthetic that is applied to a body surface such as the skin or mucous membrane
Dental advantages of topical anesthetic
- Pain control
- Increased patient comfort
- Reduction of patient’s gag reflex
Mechanism of Action of Topical Anesthetics
- Blocking nerve conduction at the surface of the skin or mucous membrane
- Permeability of sodium ions to the nerve cell is decreased, resulting in decreased depolarization and increased excitability threshold that ultimately blocks the conduction of the nerve impulse and produces a reversible loss of sensation.
What is Methemoglobinemia?
A condition in which a form of hemoglobin called methemoglobin builds up in the blood and oxygen is unable to be carried effectively to body tissues.
Kovacaine Mist
- New product that delivers dental anesthetic by way of nasal spray
- HCL combination is administered via the nasal mucosa and diffuses into the maxillary dental plexus.
- Clinical trials have been completed.
Benzocaine
- Ester
- Most common dental concentration is 20%
- Rapid onset of action: 30 seconds to 2 minutes
- MRD not established; doesn’t exist
- Duration: 5 to 15 minutes
- Metabolized via hydrolysis in the plasma and by cholinesterase in the liver
- Excretion primarily through kidneys
- Pregnancy/Lactation: FDA Category C
- Methemoglobinemia
Lidocaine
- Amide
- Available in base or hydrochloride salt
- Available concentration: 2% or 5% preparations
- Onset of action: Between 2 and 10 minutes
- Duration: 15 to 45 minutes, depending on method of application
- MRD: 200 mg
- Metabolized in liver; excreted via kidney (<10% unchanged)
- Pregnancy/Lactation: FDA Category B
Dyclonine Hydrochloride
- Not an ester; not an amide; it is a ketone
- Prescription for topical use; OTC – Sucrets Lozenges
- Dental formulation: 0.5% or 1% solutions
- Slow onset of action; may take 10 minutes
- Average duration: 30 minutes; may last up to 1 hr
- MRD: 200 mg (40 mL of 0.5% solution or 20 mL of 1% solution)
- No information on metabolism/excretion
- Pregnancy/Lactation: FDA Category C
Tetracaine Hydrochloride
- Topical preparations: Combined with other drugs
- Ester
- Available concentration: 2% (topical)
- Slow onset of action: Peak effects 20 minutes
- Duration: approx. 45 minutes
- MRD: 20 mg (topical); 1 mL of 2% solution
- Metabolized by plasma pseudocholinesterase
- Excreted in kidneys
- Pregnancy/Lactation: FDA Category C
Benzocaine, Butamben, and Tetracaine (Cetacaine)
- All esters
- Benzocaine 14%, butamben 2%, and tetracaine hydrochloride 2%
- Rapid onset of action: —–Approximately 30 seconds
- Duration: 30 to 60 minutes
- MRD: Spray administered for 1 second; gel and liquid 200 mg
- Hydrolysis via cholinesterase
- Pregnancy/Lactation: FDA Category C
- Tetracaine is very lipid soluble = rapid absorption
Oraqix: 2.5% Lidocaine and 2.5% Prilocaine Gel
-Purpose
To provide comfort to gingival tissues during prophylaxis, periodontal assessment, and nonsurgical perio therapy
-Lidocaine and prilocaine are amides.
-Available concentration: 5% periodontal gel
-Onset of action: By 30 seconds
-Duration: 20 minutes (range 14 to 31 minutes)
-MRD: 5 cartridges at one treatment session
-Metabolized in liver
-Pregnancy/Lactation: FDA Category B
-Do NOT inject!
Adverse Effects of Topical Anesthetics
- Irritation
- Stinging or burning at the site of application
- Sloughing
- Tissue discoloration
- Temporary alteration in taste perception
- Excitatory effects of central nervous system (CNS)
- Cardiovascular system (CVS)
Avoiding Toxic Reactions from Topical Anesthetics
- Know the relative toxicity of the drug being used.
- Know the drug concentration.
- Use the smallest volume.
- Use the lowest concentration.
- Use the least toxic drug possible.
- Limit the area of application.
