Monday, December 19, 2005
Doctors today presented more evidence that it's time for long-time antibiotic stalwarts like penicillin and amoxicillin to step aside when it comes to the treatment of strep throat.
The most common medications used to treat the strep germ, the bug that causes millions of sore throats in U.S. children every year, simply aren't doing the job and aren't as effective as newer antibiotics known as cephalosporins. In results presented today at a large infectious disease meeting, the annual Interscience Conference on Antimicrobial Agents and Chemotherapy in Washington, doctors who reviewed the treatment given to 11,426 children showed that even a short course of the newer drugs is more effective than the traditional 10-day dose of the older antibiotics.
Pediatricians at the University of Rochester Medical Center found that 25 percent of children treated for strep throat with penicillin ended up back in the doctor's office within three weeks of treatment. Children treated with amoxicillin returned 18 percent of the time. The numbers were 14 percent for older-generation cephalosporins, and just 7 percent for newer ones like cefpodoxime and cefdinir, which are given for just four or five days.
The new results buttress previous work by physicians Michael Pichichero, M.D., and Janet Casey, M.D., showing that more children who receive the older drugs relapse, prolonging their illness and forcing doctors to turn to even stronger drugs. Yet, said Pichichero, doctors across the land continue to prescribe ineffective medications. Studies have shown that approximately 60 to 80 percent of children treated for strep are prescribed amoxicillin; 10 to 20 percent are prescribed penicillin; and just 10 to 20 percent receive a cephalosporin.
"Most doctors are shocked to learn of the high failure rates of the older medications," said Pichichero, a professor of Microbiology and Immunology.
"The treatment paradigm for treating strep sore throats has been changing slowly, and endorsing the use of cephalosporins as a first-line treatment is something that needs to be seriously considered," Pichichero said.
While the newer short-course cephalosporins are only available in brand-name form and are much more expensive, older ones such as cephalexin (better known as Keflex) cost about the same as penicillin or amoxicillin but are more effective against strep.
The study was a meta-analysis - a combination of statisitics from other studies which are crunched anew to get new results. These numbers are from an "extension" of a previous study published by the authors. It isn't clear how the extension improves on the last one. It, too, was a meta-analysis, but it had some problems:
Although the authors have gone to considerable lengths to provide a "clean" and reliable meta-analysis, their published results are missing vital data. Reporting only odds ratios provides a relative comparison of cephalosporins and penicillin, but the absolute numbers relating to cure rates and other outcome measures also are needed so that the clinical significance of any differences can be assessed. For example, if the failure rate with a cephalosporin was 2 percent while the failure rate of penicillin was 4 percent, it could be said that treatment failure was twice as common with penicillin, and perhaps it could then be inferred that penicillin should not be used. If the absolute numbers are reviewed, however, the clinical significance of a 96 percent or a 98 percent success rate would be much more debatable.
In the meta-analysis reviewed here, some individual trials favored cephalosporins while others favored penicillin, leading one to suspect that, overall, these antibiotics had largely similar effects. An accompanying editorial1 questions the importance of the 5.4 percent absolute difference in eradication rates from the pooled studies, concluding, for this and other reasons, that "penicillin at this time remains the drug of choice.
We need to see more than the press release to know if the current meta-analysis is any more clinically significant, although if the statement that 25% of children treated with penicillin return for re-treatment compared to 7% for newer cephalosporins - that is a tremendous difference. But, what we need to know is whether or not these were the first and only drugs used before they returned and did they have culture proven strep throat, or just "sore throats?" We eagerly await the data.
UPDATE: Received an email with the abstract. The new study includes 47 different trials in its analysis. The old one, involved only thirty five trials. But, at least in the abstract, the results are only expressed, again, in terms of odds ratios. We still eagerly await a published paper, and the data. (At least those of us who spend a good portion of our day doling out Penicillin for strep throat, do.)
posted by Sydney on 12/19/2005 08:33:00 AM 0 comments