Inclusion Criteria:

• Men and women age 50-years or older.
• Patients with symptomatic osteoarthritis of the knees as defined by the American College of Rheumatology criteria(traditional format).
• At least moderate pain in the knee (rated at 40 or greater by the subject on a visual analogue scale) for most days during the last month.
• Use of analgesic or anti-inflammatory agents for control of pain for at least 1 month.
• Baseline functional capacity class 1 to 3, in which class 1 is complete ability to carry out usual activities without handicap,class 2 is ability to adequately conduct usual activities despite handicap of discomfort or limited mobility of one or more joints,and class 3 is limited ability to carry out usual activities. (American Rheumatism Association functional class)
• Documented radiographic changes of osteoarthritis on a previous knee radiograph (Kellgren-Lawrence grade of 2 or more).

Exclusion Criteria:

• Age <50-years.
• Body mass index (BMI) equal to or greater than 35 kg/m2.
• Baseline functional class 4 with the subject bedridden or confined to wheelchair, largely or wholly incapacitated and capable of little or no self-care. (American Rheumatism Association functional class)
• Inflammatory arthritis, gout, pseudogout, or Paget's disease.
• Presence of chronic pain syndromes, such as fibromyalgia or reflex sympathetic dystrophy, that may interfere with the assessment of joint symptomatology.
• Severe bursitis of the knee.
• History of acute joint trauma within 30 days of study entry.
• Complete loss of articular cartilage.
• History of total knee replacement.
• Intra-articular/intramuscular corticosteroids within 30 days of study entry.
• Intra-articular hyaluronan and hyalans within 30 days of study entry.
• History of gastrointestinal bleeding within 1 year of study entry.
• Active peptic ulcer disease, gastroesophageal reflux disease, or inflammatory bowel disease.
• Gastrointestinal tract ulceration within 30 days of study entry.
• Severe renal dysfunction defined as a serum creatinine greater than 2 mg/dL.
• Clinically significant liver disease including an aspartate aminotransferase or alanine aminotransferase >2 times the upper limit of normal.
• Unwillingness or inability to abstain from ethanol for the study duration.
• Significant bleeding disorder.
• History of gastric or duodenal surgery.
• Warfarin use.
• Sensitivity to acetaminophen or to any of the components of Myalgesin™.
• Pregnancy.
• Any serious medical, social or psychological condition that, in the opinion of the Principal Investigator, would disqualify a subject from participation.