The duration of local anesthesia of procaine is about 1 hour, and the effect can be maintained for 1 to 2 hours if a trace amount of epinephrine is added to the liquid. It has weak penetration of the skin and mucous membranes and is not suitable for use as surface anesthesia. After absorption, this product is mainly hydrolyzed to p-aminobenzoic acid and diethylaminoethanol by plasma pseudocholinesterase. The former can compete with the antibacterial effect of anti-sulfanilamide drugs and weaken the efficacy of sulfanilamide Chemicalbook drugs. The latter can enhance the effect of digitalis, and patients who have taken sufficient digitalis should use this drug with caution. When procaine is combined with succincholine, both drugs are hydrolyzed by plasma pseudocholinesterase. In the case of intravenous infusion of large amounts of procaine, it is possible to compete with the hydrolytic enzyme and reduce the hydrolytic inactivation of succincholine, significantly strengthen and prolong its muscle relaxation effect, resulting in respiratory paralysis.