Eucaine

EUCAINE (eucaine, evkain), Eucaine. The study of cocaine (see) showed that its anesthetic action is associated with a specific combination in the molecule of a benzoic acid residue (C₆H₅COO-) with a nitrogenous base. Since cocaine contains a piperidine ring in its nitrogenous base, a number of attempts were made to find esters of benzoic acid with variously substituted piperidines. Of these compounds, called E., only beta-eucaine is used, the hydrochloride salt of the benzoyl-trimethoxy-piperidine ester n n n ch₃\/___\/ < )COO /<______/NH-HCl n /\ /\ H H CH₃ CH₃, a white crystalline powder with a slightly bitter taste, easily soluble in alcohol, soluble 1:30 in water; melting point 268°, with decomposition. Beta-E. is 4-5 times less toxic than cocaine, and its anesthetic action is in strength close to the latter; it barely dilates the pupils, does not disturb accommodation, however slightly dilates blood vessels; by adding adrenaline to a solution of beta-E., blood vessels can be constricted when using such a solution and the local anesthetic action of E. can be enhanced. Solutions of E. have a slight antiseptic effect. Poisoning from beta-E. occurs with large doses; symptoms of poisoning are similar to those from cocaine, only convulsions are less severe and not so prolonged, and the heart contracts more slowly; due to the dilation of peripheral vessels by E. and significant blood flow to them, the heart is insufficiently filled with blood. In ophthalmic practice, eucaine is used in a 2% solution; for infiltrative anesthesia - 0.1-1-2% solution; for regional anesthesia - 2-5% solution; for ischias - 70-100 cm³ of 0.1% solution in physiological solution is injected along the nerve. The dose of beta-E. of 0.1-0.12 should be considered maximum, and 0.2 is already toxic.