CHLOROPROCAINE, LIKE OTHER LOCAL ANESTHETICS, BLOCKS THE GENERATION AND THE CONDUCTION OF NERVE IMPULSES, PRESUMABLY BY INCREASING THE THRESHOLD FOR ELECTRICAL EXCITATION IN THE NERVE, BY SLOWING THE PROPAGATION OF THE NERVE IMPULSE AND BY REDUCING THE RATE OF RISE OF THE ACTION POTENTIAL. IN GENERAL, THE PROGRESSION OF ANESTHESIA IS RELATED TO THE DIAMETER, MYELINATION AND CONDUCTION VELOCITY OF AFFECTED NERVE FIBERS. CLINICALLY, THE ORDER OF LOSS OF NERVE FUNCTION IS AS FOLLOWS: (1) PAIN, (2) TEMPERATURE, (3) TOUCH, (4) PROPRIOCEPTION, AND (5) SKELETAL MUSCLE TONE.
SYSTEMIC ABSORPTION OF LOCAL ANESTHETICS PRODUCES EFFECTS ON THE CARDIOVASCULAR AND CENTRAL NERVOUS SYSTEMS. AT BLOOD CONCENTRATIONS ACHIEVED WITH NORMAL THERAPEUTIC DOSES, CHANGES IN CARDIAC CONDUCTION, EXCITABILITY, REFRACTORINESS, CONTRACTILITY, AND PERIPHERAL VASCULAR RESISTANCE ARE MINIMAL.