Antibiotic treatment of incipient drug-induced gingival overgrowth in adult renal transplant patients

Background: Drug-induced gingival overgrowth (GO) remains a challenge in periodontics. Partial and total regressions of this GO have been reported after a short course of antibiotics. Methods: We conducted a double-blinded controlled randomised study to determine the effect of metronidazole (MNZ) or azithromycin (AZM) on the regression of incipient cyclosporin A-induced GO in 40 adult renal transplanted patients. The quantitation of the GO was performed with Image Digital Analysis. Results: None of the patients with GO showed complete remission after 30 days. The pretreatment GO index was 0.895 +/- 0.16 in the metronidazole treatment group (MNZ group, n = 13), 0.932 +/- 0.11 in the azithromycin treatment group (AZM group, n = 14), and 1.073 +/- 0.32 in the controls (placebo group, n=13). At the end of the study (30 days), the GO index score was lower in 54.4% and 62.3% of the MNZ and AZM groups, respectively, and the mean score differences were statistically significant between the groups (0.897 +/- 0.28, MNZ group vs. 0.909 +/- 0.15, AZM group VS. 1.130 +/- 0.3, placebo group, P < 0.05 ANOVA). Conclusions: A 7-day course of MNZ or AZM does not induce remission of CsA-induced GO, although it acts on concomitant bacterial over-infection and gingival inflammation.