Topical Anesthesia of the Unbroken Skin

The purpose of this study was to attempt to produce anesthesia of the unbroken skin by topical application of anesthetic salts or their bases. Certain volatile substances, such as menthol, phenol, or benzyl alcohol, readily penetrate unbroken skin and are not a part of this report. Anesthesia following topical application of anesthetic salts is easily produced when applied to the oral, nasal, or conjunctival mucosa. Similar anesthesia of the unbroken skin is more difficult because of the skin barrier to epicutaneous penetration. Materials Both solutions and ointments were used as vehicles for a number of anesthetic drugs and of an antihistaminic drug with anesthetic properties. The drugs used were lidocaine (Xylocaine), tetracaine (Pontocaine), phenacaine (Holocaine), procaine, benoxinate (Dorsacaine) and tripelennamine (Pyribenzamine). The bases of these drugs were dissolved in a solution containing 45% isopropyl alcohol, 10% glycerin, and 45% water, hereafter called the alcoholic solvent. This