Tramadol extended-release in the management of chronic pain

Chronic, noncancer pain such as that associated with osteoarthritis of the hip and knee is typically managed according to American College of Rheumatology guidelines. Patients unresponsive to first-line treatment with acetaminophen receive nonsteroidal antiinflammatory drugs (NSAIDs), including cyclooxygenase-2 (COX-2) inhibitors. However, many patients may have chronic pain that is refractory to these agents, or they may be at risk for the gastrointestinal, renal, and cardiovascular complications associated with their use. Tramadol, a mild opioid agonist and norepinephrine and serotonin reuptake inhibitor, is recommended by current guidelines for the treatment of moderate to moderately severe pain in patients who have not responded to previous oral therapy, or in patients who have contraindications to COX-2 inhibitors and nonselective NSAIDs. An extended-release (ER) formulation of tramadol was approved by the US Food and Drug Administration in September 2005. In contrast with immediate-release (IR) tramadol, this ER formulation allows once-daily dosing, providing around-the-clock analgesia. In clinical studies, tramadol ER has demonstrated a lower incidence of adverse events than that reported for IR tramadol. Unlike nonselective NSAIDs and COX-2 inhibitors, tramadol ER is not associated with gastrointestinal, renal, or cardiovascular complications. Although tramadol is an opioid agonist, significant abuse has not been demonstrated after long-term therapy. It is concluded that tramadol ER has an efficacy and safety profile that warrants its early use for the management of chronic pain, either alone or in conjunction with nonselective NSAIDs and COX-2 inhibitors.