Oxymorphone Extended-Release Tablets (Opana ER) For the Management of Chronic Pain: A Practical Review for Pharmacists.

Whether in a dedicated pain-management clinic or in a community pharmacy, pharmacists can provide valuable education and treatment recommendations to patients and clinicians. Pain programs, jointly managed by pharmacists, nurse practitioners, specialists in behavioral medicine and functional restoration, and specialty pain physicians, can enhance the satisfaction of patients and health care professionals, improve clinical outcomes, and minimize the need for secondary pain referrals.1 Pharmacists who become knowledgeable in pain pharmacotherapy can facilitate safe, effective, and cost-beneficial equianalgesic opioid conversions in primary care settings.2 Long-acting (LA) opioids are recommended for moderate-to-severe chronic cancer and non-cancer pain.3,4 In their most recent evidence review, the American Pain Society and American Academy of Pain Medicine concluded that there is insufficient evidence to recommend that LA opioids be used in place of short-acting opioids for chronic non-cancer pain, but they acknowledge that LA opioids might provide more consistent pain control, improve adherence, and reduce the risk of addiction or abuse.4 Additional research is needed to evaluate these proposed advantages.5 Differences among opioids influence individual patient response and tolerability, risks and benefits in specific disease states, the likelihood of drug interactions, and ease of monitoring. Differences among patients with respect to genetic factors, age, sex, and the prior use of opioids also contribute to variability of response to individual opioids.6 Consequently, when selecting LA opioids, clinicians cannot reliably predict how a given patient will respond. Patients with chronic pain usually require consecutive trials of several LA opioids before they find one that provides adequate analgesia with acceptable tolerability.7–9 For this reason, it is essential to have multiple LA opioids from which to choose. In 2006, the FDA approved extended-release oxymorphone HCl (Opana ER, Endo) for the control of moderate-to-severe chronic pain. At that time, morphine (MsContin, Purdue); Oramorph SR, Xanodyne; oxycodone (OxyContin, Purdue); methadone (Dolophine, Roxane); and transdermal fentanyl (Duragesic, Ortho-McNeil-Janssen) were the only LA opioids approved in the U.S., and they remain the primary alternatives to oxymorphone ER today. Some pain specialists do not consider LA tramadol (Ultram, PriCara) to be an equivalent alternative to these drugs because of its predominantly non-opioid mechanism of action10 and relatively weak analgesic potency, compared with other more potent opioids. LA hydromorphone (Palladone, Purdue) was withdrawn from the U.S. market in 2005 because of a potentially fatal interaction with alcohol.11 A new formulation (Exalgo, Covidien) has received FDA approval.12,13 Transdermal buprenorphine (e.g., Transtec, Butrans, or Norspan in Europe) is being studied for the management of chronic pain. It will probably represent another LA opioid choice if it receives FDA approval.14 Tapentadol (Nucynta, PriCara) combines mu-opioid receptor agonism with norepinephrine reuptake inhibition. It is available as an immediate-release (IR) tablet, and a long-acting preparation is being investigated.15 Tapentadol is featured in this month’s Drug Forecast column on page 330. A Schedule II controlled substance (CII), oxymorphone ER is a selective mu-opioid agonist16 that is embedded in an agglomerated hydrophilic matrix to provide sustained activity over a 12-hour dosing interval.17 This article describes the agent’s pharmacology, pharmacokinetics, efficacy and safety, and clinical considerations of significance to pharmacists, clinicians, and members of P&T committees.