DOES CARBAMAZEPINE HAVE A NARROW THERAPEUTIC PLASMA-CONCENTRATION RANGE

Recently, there has been considerable discussion regarding the classif ication of drugs as a function of their therapeutic index, defined as the ratio between the upper and lower limits of the therapeutic range. Pharmacologic agents with a therapeutic index <2 are classified as '' narrow therapeutic index'' (NTI) drugs, One of the agents classified a s an NTI drug is carbamazepine. These recent developments led us to ev aluate critically the evidence supporting the classification of carbam azepine as an NTI drug to address an old question: ''Does carbamazepin e have a narrow therapeutic plasma concentration range?''