The Role of Acetaminophen in Early Osteoarthritis

The overall management of pain and osteoarthritis (OA) has always been areas of focus for managed care. Pain has traditionally been classified as acute, chronic malignant, and chronic nonmalignant. Acute pain has historically not been an area of emphasis for managed care given the short-term utilization and generic availability of pain medications. However, OA is one of the most prevalent conditions encountered by healthcare providers and is estimated to be the most common cause of disability in adults.^1,2

Furthermore, the most significant and life-altering component of OA is pain (both acute and chronic). As the population ages, the incidence of OA is likely to increase even more. From a patient and managed care viewpoint, the costs of managing OA can be substantial and include a negative impact on quality of life; direct costs associated with treatment, such as medications, physician visits, and joint replacement surgeries; and indirect costs, such as lost productivity. To quantify this burden, a study published in late 2009 estimated total costs related to the care of OA for insurers and patients to be $185.5 billion.^3-7

Guidelines for the treatment of OA should encourage nonpharmacologic therapy, and when pain relief is required, initial use of less expensive medications where appropriate. For noninflammatory OA, the drug of choice is acetaminophen (acetyl-para-aminophenol [APAP]).^8-11 APAP is an effective pain reliever, and adverse effects are generally mild. APAP is also very inexpensive and highly accessible since it is available without a prescription (ie, over the counter). This also allows an opportunity for self-care, but only as directed by a physician. It is important to monitor for maximum dose-especially since many combination agents contain APAP-and for hepatotoxicity with chronic use. APAP also has a critical role in treating breakthrough pain. Opioid analgesics are effective pain relievers but should be avoided for long-term use.^9-11 Opioids have significant adverse events, many of which are exacerbated in elderly patients (who typically have a higher incidence of OA). Furthermore, opioids are associated with issues of drug dependence and substance abuse. For chronic severe pain, long-acting opioids may be considered, but appropriate use is critical and these agents are typically very expensive. Nonsteroidal anti-inflammatory drugs (NSAIDs) may be used in patients who fail to respond to APAP, for those with moderate-to-severe pain, or in inflammatory pain. NSAIDs are effective pain relievers but are associated with a high risk of adverse events, especially those of the gastrointestinal (GI) tract.^9-11 Cyclooxygenase-2 inhibitors are associated with the risk of GI and cardiovascular events, and they are relatively expensive. NSAIDs are also associated with significant drug interactions and a potential for renal toxicity. Historically, there is a correlation between chronic NSAID use and increased utilization of gastroprotective agents, which significantly increases polypharmacy issues and cost, and exacerbates the potential for drug interactions.

The subsequent articles will delve into the issues surrounding the use of APAP in OA, specifically looking at the comparative efficacy of APAP and NSAIDs, the safety concerns of these pharmacologic options, their impact on quality of life, and the economic burden of OA. From a provider and managed care perspective, the goals of managing OA are to control pain, minimize disability, and improve quality of life. APAP, when used appropriately, is a very cost-effective and safe treatment option for OA and will help all stakeholders meet the goals of treatment.

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9. Zhang W, Moskowitz RW, Nuki G, et al. OARSI recommendations for the management of hip and knee osteoarthritis, part II: OARSI evidence-based, expert consensus guidelines. Osteoarthritis Cartilage. 2008;16(2):137-162.

10. Jordan KM, Arden NK, Doherty M, et al. EULAR recommendations 2003: an evidence based approach to the management of knee osteoarthritis: report of a Task Force of the Standing Committee for International Clinical Studies Including Therapeutic Trials (ESCISIT). Ann Rheum Dis. 2003;62(12):1145-1155.

11. American College of Rheumatology Subcommittee on Osteoarthritis Guidelines. Recommendations for the medical management of osteoarthritis of the hip and knee: 2000 update. Arthritis Rheum. 2000;43(9):1905-1915.

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