This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Pallasch, T. Articles by Thomas, J. G. Search for Related Content PubMed PubMed Citation Articles by Pallasch, T. Articles by Thomas, J. G.

(Arteriosclerosis, Thrombosis, and Vascular Biology. 2004;24:e163.)
© 2004 American Heart Association, Inc.

Letters to the Editor

Subantimicrobial Doses of Tetracycline

Thomas Pallasch

University of Southern California, Los Angeles, CA

An extract of the first 250 words of the full text is provided, because this article has no abstract.

To the Editor:

The April issue of Arteriosclerosis, Thrombosis, and Vascular Biology contains an article by Brown et al regarding the use of "subantimicrobial doses of doxycycline" as an inhibitor of matrix metalloproteinases, using 40 mg of doxycycline (20 mg twice a day).¹ This group has claimed in the past and intimated in this article that such doses are too low to affect bacteria and hence will not disturb the indigenous microbial flora or induce or select microbial resistance. Such claims are simply inaccurate.

Such 20-mg, twice daily doses of doxycycline daily produce blood levels of 0.79 micrograms/mL (±0.285 micrograms/mL), as clearly stated by the proponents of this dosing for the "management" of periodontal disease.^2,3 Doxycycline is effective in the management of infectious diseases at serum dose levels 0.04 micrograms per ml⁴ and has been life-saving (infections caused by vancomycin-resistant enterococci and staphylococci) at blood levels of 0.06 to 0.25 micrograms/mL.³

Tetracyclines are paramount in the antimicrobial armamentarium as promoters of microbial resistance gene transfer and as inducers of resistance gene expression.³ Tetracycline resistance genes are also very commonly associated with the resistance genes for other antibiotics in integrons.³ To select for one resistance gene is likely to select for all. Only nanomolar amounts of tetracycline are required to derepress the efflux system that forms their major mechanism for resistance.⁵ Tetracycline stimulates colonic microbial resistance gene transfer in Escherichia coli which may only occur when the drug is present.³ Microbes use nanograms of antibiotics to control their ecology, and to . . . [Full Text of this Article]

David L. Brown

Department of Medicine, Beth Israel Medical Center, New York, NY, and Albert Einstein College of Medicine, Bronx, NY

Lorne M. Golub

Department of Oral Biology and Pathology, School of Dental Medicine, State University of New York, Stony Brook, NY

John G. Thomas

Departments of Pathology and Periodontics, West Virginia University Schools of Medicine and Dentistry, Morgantown, WV