Oxymorphone / Noroxymorphone

Common/Brand Names
Opana, Numorphan
Expected Screen Results
Oxycodone
Expected Confirmation Results
Oxymorphone / Noroxymorphone
Confirmation Cutoff
20
ng/mL
Detection Time
Up to
3
Days
Notes
Oxymorphone is a drug and also metabolite of oxycodone; Some preliminary screens may be positive for oxycodone and opiates. Noroxymorphone is the metabolite of oxymorphone, as well as Naloxone.
drug image

INTRODUCTION

Oxymorphone, a Schedule II semi-synthetic opiate derived from thebaine, possesses a structure similar to that of morphine, which makes it part of phenanthrenes group1. Additionally, this drug is a µ receptor agonist and is 5-10 times more potent than morphine1,2. It is prescribed as a narcotic analgesic for moderate to moderately severe pain under the following trade name: Opana. Prescriptions for oxymorphone have increased from approximately 268,000 in 2007 to 1.22 million in 20123.  

PHARMACOLOGY                                            

ADMINISTRATION:

Oxymorphone is administered orally in tablet form with typical doses of 5-10 mg or as an extended release with a dose of 5-40 mg.  Additionally, it may be administered as a 1 mg/mL solution for parenteral injection5.

DISTRIBUTION:

Following a 5-20 mg oral dose of oxymorphone, peak plasma concentrations occurred around 0.5 hours with a half-life of 4-12 hours5.

METABOLISM:

Oxymorphone is extensively metabolized via glucuronidation and reduction, with greater than 95% of the dose metabolized to form conjugated oxymorphone along with minor amounts of 6-oxymorphol5.

EXCRETION:

Approximately 1.9% of parent drug, 44% of conjugated hydromorphone, and traces of minor metabolites are excreted in the 120 hour urine5.

METHODS OF ANALYSIS

For qualitative analysis, oxymorphone demonstrates poor cross-reactivity with the opiate assay; therefore, the highly specific oxycodone screening Enzyme Immunoassay (EIA) methodology is utilized with an approximately equivalent cutoff concentration of 300 ng/mL6. Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry (UPLC-MS/MS) is used to confirm and quantify oxymorphone, with a cutoff concentration of 20 ng/mL. The urine samples are hydrolyzed prior to analysis and the total oxymorphone concentration is reported.

INTERPRETATION

The interpretation of patients prescribed oxymorphone should be conducted with caution since it is a prescription drug and a metabolite of oxycodone. Patients prescribed oxymorphone should not have oxycodone present in their urine. However, oxymorphone preparations may contain hydromorphone and oxycodone as an impurity up to 0.1% and 0.4%, respectively7.

References
  1. Ropero-Miller. J.D., Goldberger.B.A (2001) Opioids. In Shaw.L.M. (eds). The Clinical Toxicology Laboratory Contemporary Practice of Poisoning Evaluation, Chapter 6. AACC Press. Washington, D.C., 73-95.
  2. Stout, P. R.  (2009) Opioids. In Ropero-Miller J. D., Goldberger B.A. (eds.) Handbook of Workplace Drug Testing 2nd edition, Chapter 10.  AACC Press. Washington, D.C., 289-316.
  3. Drug Enforcement Administration. (2013) Oxymorphone. Retrieved from deadivision.gov. http://www.deadiversion.usdoj.gov/drug_chem_info/oxymorphone.pdf.
  4. Food and Drug Administration (2011) Opana tablets, CII (3155047). Retrieved from fda.gov.  http://www.accessdata.fda.gov/drugsatfdadocs/label/2012/02161107lbl.pdf.
  5. Baselt, R. C. (2011) Disposition of Toxic Drugs and Chemicals in Man, 9th Edition. Biomedical Publications, Seal Beach, CA, 1265-1266.
  6. DRI Oxycodone Assay [Package Insert]. Fremont, CA: Thermo Scientific.
  7. American Association of Medical Review Officers. (2010) Interpreting Test Results for Prescription Opiates. MRO Alert,3, 1-3.