Topical anesthetics

Application

Mucous membrane to anesthetize the terminal nerve endings (2-3mm) thus increasing patient comfort during needle penetration

Concentration

• Concentration of topical anesthetic is higher than the same agent that will be injected

• Higher concentration facilitates diffusion of the drug through the mucous membrane or abraded skin

Vascular absorption

• Topical anesthetics do not contain vasoconstrictors and anesthetics (injectable) are vasodilators, so absorption is rapid

• Levels of topical anesthetic may reach similar levels of the injectable anesthesia

Benzocaine

• Ester (plasma)

• Availability (Cetacaine, Hurricaine)

• Not suitable for injection

• Available as a liquid, gel, ointment, and spray

• Onset is approximately 30 seconds after application, recommend applying for 1-2 minutes

• Duration of 5-15 minutes

Topical Anesthetics: Oral gels

• Topicale

• Anbesol

• Baby Orabase

• Topex

• Orajel

• Etc.

Dyclonine Hydrochloride Dyclone

• Ketone

• .5% solution, 200 mg

• Used as a rinse, or applied with a cotton tip applicator

• Onset is up to 10 minutes

• Duration-may be up to one hour

• Systemic toxicity–rare

Cetacaine

• Benzocaine

• Ester

• Liquid

• Rapid anesthesia- within

30 seconds

• Duration is 30-60 minutes

Lidocaine

• Topical or water soluble preparation

• Amide

• Lidocaine ointment, 200 mg dose

• Exceptionally low incidence of allergic reactions

• Xylocaine, Octocaine

EMLA (Eutectic Mixture of LA)

2.5% Lidocaine

2.5% Prilocaine

Allergic response to topical anesthesia

• Esters (benzocaine and tetracaine)

• Allergic response is usually local