Oral oxymorphone for pain management

Abstract

Objective: To describe the pharmacology, safety and efficacy, and rationale for use of oral oxymorphone for the management of acute and chronic moderate-to-severe pain.

Data sources: A PubMed/MEDLINE search (1966-March 2007) was conducted using the following terms: oral oxymorphone, oxymorphone, EN 3202, EN 3203, Opana, and Opana ER. Manufacturer-provided data (package inserts) and abstracts presented at the American Pain Society meetings (2003-2006) were also reviewed.

Study selection and data extraction: Human studies evaluating the safety and efficacy of oral oxymorphone in pain management were considered; animal and non-English-language data were excluded.

Data synthesis: Oral oxymorphone is a semisynthetic opioid agonist that is specific for the mu-opioid receptor and approved to treat both acute and chronic pain. Unlike other opioids, such as oxycodone, oxymorphone does not bind to the kappa-opioid receptor. Due to extensive liver metabolism, oral oxymorphone is contraindicated in patients with moderate-to-severe hepatic impairment; however, no clinically significant CYP3A4, 2C9, or 2D6 mediated drug-drug interactions have been noted. Elderly patients may experience a 40% increase in plasma concentrations, while renally impaired patients may have a 57-65% increase in bioavailability. Food can increase the rate of absorption by as much as 50%, necessitating dosing either 1 hour before or 2 hours after a meal. Oxymorphone's primary adverse effects are similar to those of other opioids: nausea, vomiting, pruritus, pyrexia, and constipation.

Conclusions: Oxymorphone is an oral therapeutic option approved for the treatment of acute and chronic moderate-to-severe pain. Oxymorphone has a safety and efficacy profile similar to that of other commonly used pure opioids (morphine, oxycodone, hydromorphone). Like oxycodone and morphine, oxymorphone also has immediate-release and extended-release formulations. Since cost alone is not yet favorable for oxymorphone over oxycodone or morphine, further studies of comparative efficacy targeting potential advantages of oxymorphone over other opioids are necessary before considering it for addition to a formulary.