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1

Topical Anesthetic

Anesthetic that is applied to a body surface such as the skin or mucous membrane

2

Dental advantages of topical anesthetic

-Pain control
-Increased patient comfort
-Reduction of patient’s gag reflex

3

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.

4

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.

5

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.

6

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

7

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

8

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

9

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

10

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

11

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!

12

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)

13

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.