Benzocaine is a highly insoluble powder that must be dissolved in either ethanol or acetone. A stock solution of 100 g/L is generally prepared. A water soluble form of the drug, benzocaine hydrochloride, is available. Like tricaine, buffering benzocaine hydrochloride working solutions may be necessary. Both solutions must be stored in light protected, airtight containers. Because benzocaine is hydrolyzed to para-aminobenzoic acid, this anesthetic should be avoided in animals receiving sulfonamides (Brown 1993). Concentrations typically range from 25-200 mg/L.