Combined Effect of Anti-inflammatory Dose Doxycycline (40-mg Doxycycline, USP Monohydrate Controlled-Release Capsules) and Metronidazole Topical Gel 1% in the Treatment of Rosacea

Research into the pathophysiology of rosacea suggests a central role for inflammatory mediators such as nitric oxide (NO), reactive oxygen species (ROS), and matrix metalloproteinases (MMPs). Effective treatments for rosacea, including topical metronidazole and systemic antibiotics, have anti-inflammatory activity, which may be more important than their antimicrobial activity in this setting. Phase III studies have substantiated the efficacy of anti-inflammatory dose doxycycline (40-mg doxycycline monohydrate controlled-release capsules) administered once daily for the treatment of inflammatory lesions of rosacea. Results of a 16-week, randomized, double-blind, placebo-controlled study of anti-inflammatory dose doxycycline plus topical metronidazole gel 1% for mild to moderate rosacea are presented here. At week 12, metronidazole was discontinued and patients continued on either placebo or doxycycline. Combination therapy significantly reduced inflammatory lesion counts as early as week 4 and through week 12 compared to topical metronidazole 1% gel monotherapy. The combined therapy appeared effective and well-tolerated.