I appreciate Dr. LaPorta's additions. The Physician's Compendium of Drug Therapy has a brand-name orientation, incomplete package insert information, and advertisements. Another work of this type is Physician GenRX, which gives the verbatim Food and Drug Administration (FDA) package inserts listed in alphabetical order by generic name.

Petrucco and colleagues are correct that AHFS Drug Information lacks a bibliography and includes in its appendix several types of investigational drugs. However, they are incorrect in stating that the USP Drug Information has no references or that Facts and Comparisons has no illustration section. Regarding the latter discrepancy, I suspect they were referring to the loose-leaf version used by pharmacists, not the annual hardbound edition. Regarding the Physicians' Desk Reference and its four indexes, my intention was that a person not familiar with a given drug name could not necessarily know in which index to look; editorial revision of this sentence obscured this.

The other specific points raised by Petrucco and colleagues need further explanation. I refer to USP Drug Information and AHFS Drug Information as "reorganized FDA package insert information" because I was struck by a pattern of common phraseology. I cannot comment on the intent of the editors, only the result. In citing examples, I described in as much detail as space allowed the data each reference provided. I chose lisinopril to test whether a text was willing to go beyond current FDA indications. Although Martindale may only be available every 3 years, its inclusion of drugs available in Europe and not in the United States makes it less likely to be dated and is useful for European readers.