Use of oral oxymorphone in the elderly.
OBJECTIVE
To review the pharmacodynamics, pharmacokinetics, efficacy, tolerability, dosing, and role of oral oxymorphone immediate-release (IR) and extended-release (ER).


METHODS
A MEDLINE/PUBMED search (1970 to September 2006) of English language studies. Additional references were obtained from their bibliographies.


METHODS
All human studies of oxymorphone were reviewed.


RESULTS
Oral oxymorphone IR/ER tablet formulations were approved in June 2006. Oxymorphone, a semi-synthetic -opioid receptor agonist structurally similar to hydromorphone, has an oral bioavailability of approximately 10%. Oxymorphone is extensively metabolized to oxymorphone-3-glucuronide and the active 6-hydroxyoxymorphone. Rapid clearance mandates every four- to six-hour dosing (IR) and every 12-hour dosing (ER). Hepatic impairment, renal impairment, and aging enhance systemic exposure. Oxymorphone IR was superior to placebo and oxycodone IR (acute pain studies). Oxymorphone ER was superior to placebo and equivalent to oxycodone CR and morphine CR (one acute and five chronic pain studies). Oxymorphone exhibits the expected opioid side effects, being comparable to oxycodone and morphine in clinical trials. Coadministration with ethanol causes "dose-dumping" (ER) and increases intersubject variability in drug absorption. Oxymorphone IR is indicated for the relief of moderate-to-severe pain, while oxymorphone ER is indicated for persistent pain. Initial doses (opioid-naïve) are 10 mg to 20 mg every 4 to 6 hours (IR) and 5 mg every 12 hours (ER). Dosage adjustment is recommended in mild hepatic impairment (Child-Pugh class A), renal impairment (creatinine clearance below 50 mL/min), and in the elderly.


CONCLUSIONS
Oxymorphone is the newest oral opioid to enter a crowded marketplace now totaling 12 Schedule 2 opioids. It does not appear to have any unique assets or liabilities and should be considered as one of many oral opioids for the management of acute and persistent pain of moderate-to-severe intensity.
Department of Experimental & Clinical Pharmacology, College of Pharmacy, University of Minnesota, MN 55455, USA. guayx001@umn.edu
David R P
DR
Guay
D000284:Administration, Oral; D000368:Aged; D000701:Analgesics, Opioid / Q000008:administration & dosage* / Q000009:adverse effects / Q000737:chemistry / Q000493:pharmacokinetics; D003692:Delayed-Action Preparations; D004347:Drug Interactions; D006801:Humans; D010111:Oxymorphone / Q000008:administration & dosage* / Q000009:adverse effects / Q000737:chemistry / Q000493:pharmacokinetics; D010146:Pain / Q000188:drug therapy*; D010147:Pain Measurement; D016032:Randomized Controlled Trials as Topic
D000701:Analgesics, Opioid; D003692:Delayed-Action Preparations; D010111:Oxymorphone