Effects on the clinical indices and gingival crevicular fluid enzyme activities of the cyclical regimen of low-dose doxycycline therapy for adult periodontitis.

The purpose of this study was to determine the effect of cyclic regimen of low dose doxycycline (20 mg) or placebo therapy following scaling and root planing on clinical parameters and crevicular fluid alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase and elastase activities. Fifteen adults (13 males, 2 females) with moderate to advanced adult periodontitis were recruited for the study. The LDD-treated group (n = 8 subjects) self administered low dose doxycycline b.i.d. (20 mg, p.o.) from time (treatment) to 2 months and then no drug from 2 to 4 months and finally low-dose doxycycline b.i.d. from 4 to 6 months (i.e. "cyclical" regimen). The placebo-treated group (n = 7 subjects) was asked to take placebo capsules (containing inactive filler; i.e. starchflour) b.i.d. according to the same "cyclical" regimen. No differences were found between LDD- and placebo-treated groups regarding any of the clinical parameters and gingival crevicular fluid enzyme activities. The relative attachment gain was significantly improved in both groups. The "cyclical" regimen of low-dose doxycycline was not found to reduce alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase and elastase activities in gingival crevicular fluid of the adult periodontitis patients over a 6-month time period.