Factors determining dosages of amide-type local anesthetic drugs

The physical status of the patient (sex, age, weight, height, and underlying disease) has been thought to influence the dosage of local anesthetic drugs that can be injected without causing a systemic toxic reaction, but this belief is not supported by statistically significant data. Furthermore, previous studies of plasma levels of bupivacaine and mepivacaine showed no correlation between dosage and physical status, even when maximum dosages recommended by pharmaceutical companies were exceeded. This study of 9,287 regional blocks, using the statistical tests of multiple regression and chi square, substantiates that the occurrence of systemic toxic reactions in adults does not correlate with dosages and/or physical status of the patient when 400 mg or less of bupivacaine, 450 mg or less of etidocaine, or 500 mg or less of mepivacaine is used. Therefore, the study questions the maximum dosages established for certain local anesthetic drugs, as well as the method by which such dosages were established.