Sir, in July 2014, one of us (Rob Stepney) was bitten on the leg by a street dog in Sarajevo. The university hospital prescribed seven days' clarithromycin 500 mg bd. Rob experienced a metallic taste shortly after taking each dose, and, some days into the course, noticed that his gums no longer bled after brushing his teeth. Rob had experienced remission of gum disease on two previous occasions when taking short courses of ciprofloxacin and metronidazole as antibiotic cover for prostate biopsies, but both times bleeding had quickly resumed. Rob, who has an MSc in Pharmacology, was intrigued at the apparent link with clarithromycin, especially since in this instance the effect on his gum health was prolonged.

At his next three-monthly check-up, Alison Zalinski – his dental hygienist who was unaware of her patient's recent history – noticed a marked improvement in Rob's gum health. This has been maintained over fourteen months. Rob's account of his experience reminded Alison of two recent cases which seemed similar.

Since data are from a retrospective review of everyday clinical records details are incomplete. However, the theme common to the three cases is of improved gum health following a macrolide antibiotic taken for unrelated reasons - see Table 1.

Table 1 Patient characteristics, antibiotics taken, and periodontal scores at the last visit before antibiotic use, first routine visit following antibiotic use and at most recent check-up
Full size table

In 2008, Burrell and Walters reported that the concentration of clarithromycin in gingiva is several times higher than in serum and higher in inflamed than in healthy gum tissue.1 Although this study involved induction of experimental gingivitis in healthy subjects (through use of a maxillary stent), the clarithromycin schedule (500 mg bd) was the same as given to Rob, though for only six doses.

Along with this evidence of relevant drug distribution, our case histories of patients with gingivitis (although small in number) suggest that a short course of macrolide taken for reasons unrelated to dental health may result in periodontal improvement that lasts and may even increase with time.

Such an effect does not seem to have been reported (or, at least, is not widely known). Have others had similar experiences? If so, it might be worth conducting a randomised trial of these agents in gingivitis patients, with periodontal health and potential adverse events as endpoints.