A double-blind placebo-controlled trial of azithromycin as an adjunct to non-surgical treatment of periodontitis in adults: clinical results

Background/aims: The aim of the study was to investigate the clinical and microbiological effects of azithromycin as an adjunct to the non-surgical treatment of periodontitis in adults. Azithromycin is an antibiotic which is taken up by phagocytes and is released over long periods in inflamed tissue but requires a total of only three doses of 500 mg to produce its therapeutic effect. Method: 46 patients were treated in a double-blind placebo-controlled study with assessments at weeks 0, 1, 2, 3 6, 10 and 22. Throughout the trial measurements were made of plaque, gingival bleeding, calculus, probing pocket depths and bleeding on probing. Microbiological sampling was carried out from a selected pocket greater than or equal to6 mm at each visit. The regime employed consisted of OHI, scaling and root planing at weeks 0, 1 and 2 with reinforcement of OHI and minimal scaling at weeks 6, 10 and 22. Patients were randomly assigned to receive either azithromycin. (A), or placebo capsules, (C), 500 mg, 1 x daily for 3 days at week 2. 44 patients completed the study. Mean pocket depths were analysed using analysis of covariance in 3 groups with initial pocket depth values of 1-3 mm., 4-5 mm and greater than or equal to6 mm. Results: The results of the microbiology have been reported in a separate paper. The clinical data showed that by week 22 a lower % of pockets initially >5 = deep remained above that level in the 23 patients taking azithromycin (A), than the 21 taking the placebo (C), (A, 5.6%; C, 23.3%). Also at week 22, for pockets initially 4 mm or more, the test group had fewer pockets >3 mm deep (A, 26.1 %; C, 44.3%), fewer failing to improve in probing depth (A 6.6%; C, 21.6%) and fewer continuing to bleed on probing (A, 46.9%; C, 55.6%) when compared with the control group. Pocket depths initially 4-5 mm or 6-9 mm analysed by analysis of covariance showed lower mean pocket depths in the patients on azithromycin, at weeks 6, 10 and 22, (pockets initially 4-5 mm, p<0.001 on all occasions, pockets initially 6-9 mm, p<0.001, week 6; p<0.003, week 10; p<0.001, week 22). Conclusions: Azithromycin may be a useful adjunct in the treatment of adult periodontitis, particularly where deep pockets are present.