The alteration of serum enzyme values following intramuscular administration of lidocaine hydrochloride (10% solution) was evaluated in nine healthy young men. Mean total creatine phosphokinase (CPK) level rose almost sevenfold within eight hours of injection and remained elevated at 48 hours. Mean values of serum glutamic oxaloacetic transaminase (SGOT), lactic acid dehydrogenase fraction 5 (LDH5), and serum glutamic pyruvic transaminase (SGPT) also rose significantly but did not exceed normal limits. This study indicates that prophylactic administration of lidocaine intramuscularly will elevate certain serum enzyme values that are useful in the diagnosis of acute myocardial infarction. Subsequent isoenzyme assay of CPK and LDH, however, will clearly distinguish the origin as skeletal rather than cardiac muscle.
Zener JC, Harrison DC. Serum Enzyme Values Following Intramuscular Administration of Lidocaine. Arch Intern Med. 1974;134(1):48-49. doi:10.1001/archinte.1974.00320190050006