Within the past few years a new local anesthetic known as nupercaine has been introduced into this country. In Europe the same substance is known as percaine. It is recommended as producing anesthesia of prolonged duration. It is much more toxic than procaine, but, owing to the high dilutions in which it is possible to use nupercaine, the relative toxicity is about equalized.1 Chemically, nupercaine is known as the hydrochloride of the diethylethylenediamide of butyloxycinchoninic acid, and its structural formula is as follows: It is not related to procaine, which is the monohydrochloride of para-aminobenzoyl-diethylaminoethanol. It is colorless, odorless, easily soluble in water or saline solution and is precipitated by alkali. Nupercaine is also recommended by the manufacturers for the relief of pruritus and is put up for that purpose in the form of an ointment of hydrous wool fat and petrolatum, containing a 1 per cent nupercaine base.
Fanburg SJ. DERMATITIS DUE TO NUPERCAINE. JAMA. 1933;101(1):30–31. doi:10.1001/jama.1933.27430260001010a