Medical Health Encyclopedia

Subantimicrobial Dose Doxycycline (Periostat). Subantimicrobial dose doxycycline (SDD) is a term used for a treatment that uses very low doses (20 mg) of doxycycline (Periostat). Although doxycycline is a tetracycline antibiotic, the doses used are too low to affect bacteria. However, at these dose levels, the drug blocks MMPs -- enzymes that destroy the connective tissues holding the teeth. Periostat is taken twice a day for months. There is some concern that such long-term use may pose a risk for the development of antibiotic-resistant bacteria or other, still unknown, adverse effects. The doses used in this treatment, however, are too low to have any effect on bacteria, so some experts believe this risk is very low. In fact, several 12-month studies are reporting significant improvements in tooth attachment and pocket depth with no increased incidence of side effects. (Taking a common nonsteroidal anti-inflammatory drug, such as aspirin or ibuprofen (Advil) long with doxycycline may enhance the effectiveness of this treatment.)

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Chemically Modified Tetracyclines. Other tetracyclines are being developed that inhibit MMPs but have no antibiotic properties, which would, theoretically, avoid possible long term problems with antibiotic resistance.