The incidence of bradycardia, within this dose range, might not be dose related. Fetal acidosis has not been demonstrated by blood gas monitoring around the time of bradycardia or afterwards. These data are limited and are generally restricted to non-toxemic cases where fetal distress or prematurity was not anticipated in advance of the block. The role of drug factors and non-drug factors associated with fetal bradycardia following paracervical block are unexplained at this time. The lowest dosage that results in effective anesthesia should be used to avoid high plasma levels and serious undesirable systemic side effects.
Tolerance varies with the status of the patient.
Debilitated patients, elderly patients, acutely ill patients and children should be given reduced doses commensurate with their age and physical status. Solutions containing vasoconstrictors should be used cautiously in the presence of disease which may adversely affect the patient's cardiovascular system. Since ester-type local anesthetics are hydrolyzed by plasma cholinesterase produced by the liver, chloroprocaine should be used cautiously in patients with hepatic disease. Injections should always be made slowly and with frequent aspirations to avoid inadvertent rapid intravascular administration which can produce systemic toxicity. Chloroprocaine should be employed cautiously in persons with known drug allergies or sensitivities.