More criticism for tramadol and the use of cephalosporins in place of penicillin

EM Myths Discussed

Great topic and obviously spot on with each practice myth (“Myths in Emergency Medicine,” January ACEP Now). I wanted to provide a few comments:

1. I could not agree more about tramadol. While you mention studies that go back a while, I heard about these “non-narcotics” (according to marketers) way back in pharmacy school in the ’70s. My only objection is that you did not mention pentazocine (Talwin) and the bogus pain-medication education many docs received (courtesy of Big Pharma). I recall, in pharmacology, Talwin was a case study of bogus public relations provided to doctors (non-addicting, better choice for patients). You don’t have to wait until the 21st century to find this in the literature.
2. The second thing that frustrated me were comments about penicillin and cephalosporins. Again, spot on as an important myth, but the explanation provided did not fit with the understanding I had. If there is another nomenclature about R position substitution that follows your line, it is different from what I learned. The primary differences and chemical substitution points are well summarized here: http://chemwiki.ucdavis.edu/Biological_Chemistry/Drug_Activity/Penicillin. “Cephalosporins are the second major group of beta-lactam antibiotics. They differ from penicillins by having the beta-lactam ring as a 6 member ring. The other difference, which is more significant from a medicinal chemistry stand point, is the existence of a functional group (R) at position 3 of the fused ring system. This now allows for molecular variations to effect changes in properties by diversifying the groups at position 3.”

If you are referring to some other aspect, please let know as I try to stay up on this. Thanks again for your work—great job.

Howard J. Swidler, MD, FACEP
Emergency Medicine Consulting and Locums Lehigh Valley

From the editor: Thank you for your kind words and support of ACEP Now. I appreciate your taking the time to comment about my article. There are so many myths to wade through that it was difficult to choose among them. I agree with your concerns about Talwin and also support your comments reflecting that many examples exist over the years of such myth generation.

Regarding the penicillin-cephalosporin myth, I’m glad we agree on the myth because diving into a discussion on stoichiometry, chemical structure, and organic chemistry, for me, would be like jumping into the deep end without my floaties the first time in the pool.

There are several theories discussed regarding which molecular component of the cephalosporins is actually responsible for the alleged cross-reactivity. Here is the excerpt from the article cited:

“Penicillins have a cross allergy with first-generation cephalosporins (odds ratio 4.8; confidence interval 3.7–6.2) and a negligible cross allergy with second-generation cephalosporins (odds ratio 1.1; confidence interval 0.6–2.1). Laboratory and cohort studies confirm that the R1 side chain is responsible for this cross reactivity. Overall cross reactivity between penicillins and cephalosporins is lower than previously reported, though there is a strong association between amoxicillin and ampicillin with first- and second-generation cephalosporins that share a similar R1 side chain” (Campagna, JD, et al. The use of cephalosporins in penicillin-allergic patients:A literature review, J Emerg Med. 2012;42(5):612.)