Procaine HCL Novacaine HCL(IP USP BP EP) is a local anesthetic drug of the amino ester group. Procaine causes loss of feeling (numbness) of skin and mucous membranes. Procaine HCL Novacaine HCL(IP USP BP EP) is used primarily to reduce the pain of intramuscular injection of penicillin, and it is also used in dentistry.