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Test ID: OXYCS    
Oxycodone, Serum

Useful For Suggests clinical disorders or settings where the test may be helpful

Monitoring oxycodone therapy

 

Assessing toxicity

 

Routine drug monitoring is not indicated in all patients. Because drug diversion (use of prescription drugs for recreational purposes) is a possibility, compliance monitoring is indicated in patients being treated for chronic pain requiring high doses (>40 mg twice a day)

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Oxycodone hydrochloride is an opioid analgesic with several actions qualitatively similar to those of morphine. The clearance half-life of oxycodone is approximately 3 to 6 hours.(1)

 

Although its own strong analgesic activity precludes oxycodone from being considered a prodrug, it is also converted to a highly active metabolite, oxymorphone, through the activity of the cytochrome P450 enzyme CYP2D6.(2) This conversion appears to be less of a concern for CYP2D6 poor metabolizers, since oxycodone itself still provides analgesia, than for ultra-rapid metabolizers who could be at increased risk for adverse effects.(3)

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

10-120 ng/mL

Interpretation Provides information to assist in interpretation of the test results

The minimal effective peak serum concentration of oxycodone for analgesia is 10 ng/mL from a dose of 5 to 10 mg of regular release oxycodone (Percodan).(1,4) Patients develop tolerance to oxycodone and may require larger doses for effective management of chronic pain.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Monitor patients carefully if drugs inhibiting CYP2D6 are coadministered.

Clinical Reference Provides recommendations for further in-depth reading of a clinical nature

1. Baselt RC: Oxycodone. In Dispositition of Toxic Drugs and Chemical in Man. Eighth edition. Edited by RC Baselt. Foster City, CA, Biomedical Publications, 2008, pp1166-1168

2. Riley J, Eisenberg E, Muller-Schwefe G, et al: Oxycodone: a review of its use in the management of pain. Curr Med Res Opin 2008;24:175-192

3. de Leon J, Dinsmore L, Wedlund P: Adverse drug reactions to oxycodone and hydrocodone in CYP2D6 ultrarapid metabolizers. J Clin Psychopharmacol 2003;23:420-421

4. Gutstein HB, Akil H: Chapter 21: Opioid analgesics. In Goodman and Gilman's The Pharmacological Basis of Therapeutics. 11th edition. Edited by LL Brunton, JS Lazo, KL Parker. New York, McGraw-Hill Inc, 2006. Available at: http://www.accessmedicine.com/content.aspx?aID=940653