procaine, the hydrochloride of which is called novocain. With its hydrochloride, white crystalline or crystalline powder, odorless, slightly bitter taste, followed by a sense of paralysis, easily soluble in water. The duration of local anesthesia of procaine is about 1 hour, and the effect can be maintained for 1 ~ 2 hours if a trace amount of epinephrine is added into the liquid. It is not suitable for topical anesthesia because of its weak penetration of skin and mucous membranes. After absorption, the product is hydrolyzed to p-aminobenzoic acid and diethylaminobenzene by plasma pseudocholinesterase. The former can compete against the antibacterial Chemicalbook effect of sulfonamides and weaken the effect of sulfonamides. The latter can enhance the effect of digitalis, and patients who have taken enough digitalis should use this drug with caution. If procaine is combined with succinylcholine, the two drugs are hydrolyzed by plasma pseudocholinesterase. In the case of intravenous inf