Evaluation of the Depth and Duration of Anesthesia From Heated Lidocaine/Tetracaine (Synera®) Patches Compared With 5% Lidocaine (Lidoderm®) Patches Applied to Healthy Adult Volunteers

Inclusion: 1. Subject is male or female 18-60 years of age, inclusive. 2. Subject is judged by the Investigator to be in generally good health at screening based upon the results of a medical history, physical examination, clinical laboratory profile, and 12-lead electrocardiogram (ECG). 3. Subject is willing to refrain from using any local topical preparations on the volar aspect of the forearms for 24 hours prior to each site visit. 4. Subject has normal, intact skin bilaterally at the antecubital area. 5. If female, must be of non-childbearing potential (defined as postmenopausal for at least 1 year or surgically sterile \[bilateral tubal ligation, bilateral oophorectomy or hysterectomy\]) or must be using adequate contraception (practicing one of the following methods of birth control): * Total abstinence from sexual intercourse (minimum of one complete menstrual cycle before study entry), * A vasectomized partner, * Contraceptives (oral, parenteral, or transdermal) for 3 consecutive months prior to test product administration, * Intrauterine device (IUD), or * Double-barrier method (condoms, sponge, diaphragm, or vaginal ring with spermicidal jellies or cream). 6. If female, must have a negative urine pregnancy test at Screening and at check-in of each Treatment Period. 7. Subject is willing to be blindfolded during the study and agrees to abide by all study restrictions and comply with all study procedures. 8. Able to fluently speak and understand English and be able to provide meaningful written informed consent for the study. Exclusion: 1. Subject has clinically significant ECG abnormalities at screening. 2. Subject is currently receiving class I, II, or III anti-arrhythmic agents. 3. Subject has used over-the-counter (OTC) or prescription analgesics within 24 hours prior to either study period. 4. Subject has a known allergy or history of significant adverse reaction to any component of the treatment or related compounds. 5. Subject has a history of or active use or abuse of illicit drug substance or alcohol abuse. 6. Subject has a positive urine test result for drugs of abuse or a positive ethanol breath test at the Screening Visit or check-in to Treatment Visit 1. 7. Subject has active dermatological disease of any origin that may interfere with the ability to participate. 8. Subject has denuded or broken skin on either forearm. 9. Subject has a history of unstable peripheral/vascular disease and/or hypertensive vascular disease.