Clinical Pharmacology of Local Anesthetics.By John E. Tetzlaff, M.D.Boston, Butterworth-Heinemann, 2000. Pages: 258. Price $50.00.
John Butterworth, M.D.,
As one with an interest in the care, feeding, breeding, and propagation of local anesthetics and regional anesthesia, I greatly looked forward to this new textbook on the subject. Having now read the book, I congratulate Dr. Tetzlaff on the extent and breadth of the references cited in the body of this work. Nevertheless, there are some problems. Fundamentally, the research with and about local anesthetics is presented in an undigested and uninterpreted way. In a work of this type, I would expect the author to evaluate the significance of research findings. Older, supplanted theories about local anesthetic mechanisms and toxicity should be identified as such. I would contrast this volume with Local Anesthetics , edited by G. Strichartz, 1and Local Anesthetics by R. de Jong, 2in which data are both presented and evaluated.
Throughout the text, chemical drawings of local anesthetic molecules were drawn freehand. Freehand drawings of aromatic ring structures may be acceptable in undergraduate organic chemistry notebooks but certainly are not appropriate in a published work, given the wide availability of chemical structure drawing programs (e.g. , ChemDraw; CambridgeSoft Corp., Cambridge, MA) and of plastic hexagonal templates. Perhaps the most glaring examples occur on page 126, where two different freehand renderings of ropivacaine consume much of the page.
There are also factual errors. For example, the author states that the axon can maintain conduction independent of a cell body for up to 5 h (this interval can be much longer, but depends on the species and nerve); contrasts Na and K channels, stating that, unlike K channels, Na channels conduct ions only in the open conformation (the open conformation is necessary for both channel forms); and asserts that the duration of local anesthetics is related to protein binding (this hoary chestnut persists despite there being no known connection between binding of local anesthetics to proteins in blood and the duration of local anesthetic action on the Na channel). It also seems odd that the nature of the local anesthetic binding site on the Na channel was not described in greater detail, given the extent of molecular genetic studies that have been performed in the past 5 yr. The body of experimental data comparing enantiomer-specific local anesthetic mechanisms was given limited consideration, despite the importance of optical isomerism in the development of the two local anesthetics (ropivacaine and levobupivacaine) most recently approved by the US Food and Drug Administration.
In summary, Dr. Tetzlaff should be commended for his ambition: There are few academicians bold enough to attempt a single-author textbook of this breadth. And, he has summarized nicely the clinical application of local anesthetics, whereas some other recent textbooks on local anesthetics have gotten no “closer” to a patient than to provide the pharmacokinetic parameters in humans.
