Flavocoxid, A Plant-Derived Therapy, for the Treatment of Knee Osteoarthritis

Inclusion Criteria: * Meet American College of Rheumatology (ACR) clinical criteria for knee OA * In good medical and psychological health * Able and willing to discontinue NSAIDs, natural therapies, and other pain medications for OA for 1 week prior to the first study visit and also throughout the course of the clinical trial * Knee pain rated greater than 4 cm on a 10 cm visual analog scale (VAS) * Intends to stay in the area and complete the 12-week protocol * Willing to use acceptable forms of contraception Exclusion Criteria: * Serious or unstable concomitant medical or psychological illnesses that would impair the patient's ability to complete the study * Significant cardiac disease OR history of myocardial infarction in the 12 months prior to study entry * Uncontrolled hypertension * Significant bleeding disorders. Participants who have bleeding disorders related to uncontrolled, bleeding hemorrhoids occurring in the 12 months prior to study entry are not excluded. * Uncontrolled gastrointestinal disease resulting in bleeding in the 60 days prior to study entry. Participants with controlled and uncomplicated ulcers are not excluded. * Inflammatory arthritis, gout, pseudogout, Paget's disease, or any chronic pain syndrome * Severe pes anserine bursitis, acute joint trauma, or complete loss of articular cartilage on the index knee * Intravenous, intramuscular, or intra-articular steroids to the index joint within 60 days of study screening * Alcohol, intravenous drug, or prescription drug abuse * Investigational drugs within 30 days of study screening * Current use of anticoagulants such as warfarin * Oral corticosteroids or other immunosuppressants within 6 months of study screening * Severe psoriasis requiring use of biologic immunomodulators such as alefacept, etanercept, infliximab, or cyclosporine * Hypersensitivity to analgesics, cyclo-oxygenase inhibitors, lipoxygenase inhibitors, or flavonoids * Pregnancy or breastfeeding Exclusion Criteria Postenrollment: * Abnormal laboratory test results at study screening, as determined by the investigator * Liver enzyme levels (SGOT, SGPT, alkaline phsphatase) two times the upper limit of normal * Leukocyte counts less than 3.5 times 109/L or platelet counts less than 150 times 109/L * At increased risk for cardiovascular problems based on the Framingham Cardiac Risk assessment questionnaire * Kellgren/Lawrence radiographic score of 0, 1, or 4 on x-ray of index joint taken within 12 months of study entry * Impaired renal function (creatinine greater than 1.5 mg/dl)