To the Editor:—
During a preoperative interview, it is not unusual for a patient to list in their drug history a medication by a trade name that is unfamiliar to an anesthesiologist. A reasonable response to this situation is often to review the package insert of the drug in question. Unfortunately, these inserts do not undergo periodic review and, therefore, it is not uncommon to read outdated, questionable, or even incorrect information for older drugs, especially if they are beyond patent protection. On the other hand, newer drugs should be expected to be associated with more current and thorough information. I recently read the product information for Coreg (carvedilol; SmithKline Beecham, Philadelphia, PA), which was presented in an advertisement that appeared in JAMA (volume 280, number 18, November 1998). The indication for Coreg is “hypertension and mild or moderate heart failure NYHA II or III,” and it seemed to me that this might represent an area of possible anesthetic interaction. The manufacturer apparently agreed and added a specific caution concerning “anesthetic agents that depress myocardial function, such as ether, cyclopropane and trichloroethylene .” I was struck by the combination of a relatively new drug (1995) with anesthestic agents no longer in use in the United States. This prompted me to search, via the website www.pdr.net/physician, for the Physicians Desk Reference (Medical Original Investigations, Montvale, NJ), for mention of any of these three anesthetics in this compendium of package inserts. The response rates were 5 for trichloroethylene, 13 for cyclopropane, and 156 for ether. It was also possible to find basically identical wording from the Coreg advertisement used with another drug from another company.
My inferences from this are several:(1) despite the general caution, there are no reliable data concerning interactions between Coreg and currently used inhalation anesthetics, otherwise they would have been mentioned;(2) a significant number of inserts, once created, seem to remain frozen in time; and (3) the oversight of package insert accuracy seems lacking.
Until every operating suite has access to near-instantaneous electronic data retrieval, package inserts will remain the primary quickly available preoperative source of information about drugs. In fact, even after such time, most on-line references will inevitably be largely based on maufacturer-supplied data. This is especially true for recently released drugs, and although novel or recent data have next-day availability electronically, it can remain no less difficult to erase erroneous original information, no matter how it is presented.
Therefore, I strongly request that both manufacturers and the Food and Drug Administration exert increased efforts to insure that package insert information is timely, relevant, and accurate. I would also suggest that the addition of phrases suggesting generally increased concern or caution should be discouraged unless adequately supported by experience. Such additions are well-meaning but misguided and may have unintended consequences. Conversely, when such experience has been obtained, especially after marketing, the insert requires prompt revision.