An Effectiveness and Safety Study of Acetaminophen Extended Release Caplets in the Treatment of Osteoarthritis of the Hip or Knee.

Inclusion Criteria: * Symptoms of osteoarthritis of the hip or knee for a minimum of six months * History of hip or knee pain due to osteoarthritis requiring the use of NSAIDs, acetaminophen or another analgesic agent on a regular basis (\>= three days/week) for at least three months before the screening visit * History of positive benefit with acetaminophen use for osteoarthritis pain * History (ie, at any time in the past since diagnosis) of osteoarthritis pain of the hip or knee when not taking osteoarthritis analgesic medication * Subjects must report a history of a pain level of moderate, moderately severe, or severe, a WOMAC pain score \>= 65 at baseline, and a 20% or greater increase in their pain score relative to their score at screening Exclusion Criteria: * History of surgery, including arthroscopy, or major trauma to the study joint in the previous six months before the screening visit * Grade 1 or grade 4 severity of the study joint based on the Kellgren and Lawrence radiographic criteria * Signs of clinically important active inflammation of the study knee joint including redness, warmth, and/or a large, bulging effusion with the loss of normal contour at the screening and/or baseline visits * Secondary osteoarthritis of the study joint including, but not limited to, septic arthritis, inflammatory joint disease, gout, Paget's disease of bone, articular fracture, major dysplasias or congenital abnormality, ochronosis, acromegaly, hemochromatosis, Wilson's disease, avascular necrosis, or primary osteochondromatosis * History of acute inflammatory arthritis or pseudogout of the study joint.