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Interpretive Handbook

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Test 500365 :
Drug of Abuse, Opiates Confirmation, Urine

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

Opiates (codeine, hydrocodone, oxycodone, morphine, hydromorphine) are the natural or synthetic drugs that have morphine like pharmacological action, expressed predominantly at the mu-opioid receptor. They are used primarily for relief of pain and often produce physical and psychological dependence. Opiates are readily absorbed from the gastrointestinal tract, nasal mucosa, lung, and after subcutaneous or intramuscular injection. They are excreted from the kidney primarily by glomerular filtration in both free and conjugated forms. Opiates are metabolized by cytochrome P450 enzymes, predominantly CYP 2D6 and 3A4, and uridine diphosphate glucuronosyltransferase. Patients deficient in these enzyme activities will experience adverse drug events if prescribed standard doses.

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

Detecting the presence of opiates in the urine

Interpretation Provides information to assist in interpretation of the test results

This test reports the total urine concentration; this is the sum of the unconjugated and conjugated forms of the parent drug. The parent drug is the unmetabolized form of the prescribed drug.

 

Codeine:

An adult of typical body weight (70 Kg) with normal renal and hepatic function receiving a 60-mg oral dose of codeine will excrete approximately 40% of the daily dose in urine as free codeine or the glucuronide or sulfate ester of codeine. Assuming a typical daily urine output of 1 L, the steady-state urine concentration of codeine will be in the range of 3,000 to 15,000 ng/mL. Morphine is a normal metabolite of codeine: morphine will be present at concentrations <2 to 10 times codeine as a result of codeine ingestion. Urine concentrations will be proportionally higher with higher doses. Abstinence for >4 days will result in an undetectable concentration (<100 ng/mL).

 

Morphine:

An adult of typical body weight (70 Kg) with normal renal and hepatic function receiving a 10-mg intramuscular (IM) dose of morphine will excrete <20% of the daily dose in urine as free morphine or the glucuronide or sulfate ester of morphine. Assuming a typical daily urine output of 1 L, the steady-state urine concentration of morphine will be in the range of 5,000 to 20,000 ng/mL. A patient receiving a 5-mg intravenous (IV) dose of morphine every 4 hours will excrete urine morphine concentration in the range of 10,000 to 40,000 ng/mL. Urine concentrations will be proportionally higher with higher doses. Abstinence for >4 days will result in an undetectable concentration (<100 ng/mL).

Note: The active forms of morphine in blood include morphine and morphine-3-glucuronide. These forms of morphine, plus morphine-6-glucuronide, are excreted in urine and are quantified as a single result (total morphine) in this test.

 

Hydrocodone:

An adult of typical body weight (70 Kg) with normal renal and hepatic function receiving a 10-mg oral dose of hydrocodone will excrete approximately 20% of the daily dose in urine as hydrocodone, hydromorphone, or the glucuronide or sulfate ester of hydromorphone. Assuming a typical daily urine output of 1 L, the steady-state urine concentration of hydrocodone will be in the range of 500 to 3,000 ng/mL. Hydromorphone is a normal metabolite of hydrocodone: hydromorphone will be present at concentrations approximately <2 times hydrocodone as a result of hydrocodone ingestion. Urine concentrations will be proportionally higher with higher doses. Abstinence for >4 days will result in an undetectable concentration (<100 ng/mL).

 

Hydromorphone:

An adult of typical body weight (70 Kg) with normal renal and hepatic function receiving a 5-mg oral dose of hydromorphone will excrete approximately 10% of the daily dose in urine as the glucuronide or sulfate ester of the parent drug. Assuming a typical daily urine output of 1 L, the steady-state urine concentration of hydromorphone will be in the range of 800 to 3,000 ng/mL. Hydrocodone is not a normal metabolite of hydromorphone; hydrocodone will not be present as a result of hydromorphone ingestion. Urine concentrations will be proportionally higher with higher doses. Abstinence for >4 days will result in an undetectable concentration (<100 ng/mL).

 

Oxycodone:

An adult of typical body weight (70 Kg) with normal renal and hepatic function receiving a 10-mg oral dose of oxycodone (OxyContin) will excrete approximately 40% of the daily dose in urine as oxycodone or the glucuronide or sulfate ester of oxycodone. Assuming a typical daily urine output of 1 L, the steady-state urine concentration of oxycodone will be in the range of 2,000 to 5,000 ng/mL. For higher doses of oral of oxycodone (OxyContin), the range of steady-state urine concentrations are as follows:

-20 mg: 5,000 to 15,000 ng/mL

-40 mg: 10,000 to 35,000 ng/mL

-80 mg: 30,000 to 65,000 ng/mL

Urine concentrations will be proportionally higher with higher doses. Abstinence for >4 days will result in an undetectable concentration (<100 ng/mL).

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

This test detects drugs structurally similar to morphine. Other drugs in the opioid class such as fentanyl, meperidine, methadone, and opiate antagonists such as naloxone, are not detected.

 

The presence of meperidine in a very high concentration (overdose proportions) will result in a positive screen report. The liquid chromatography-tandem mass spectrometry report will be negative for opiates.

 

While 6-monoacetylmorphine (6-MAM) is metabolized to morphine, the presence of morphine alone is not sufficient evidence to prove heroin use. 6-MAM is the only definitive metabolite of heroin.

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.

Negative

Positive cutoff concentrations

Codeine: <100 ng/mL

Hydrocodone: <100 ng/mL

Hydromorphone: <100 ng/mL

Morphine: <100 ng/mL

Oxycodone: <100 ng/mL

Oxymorphone: <100 ng/mL

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

1. Hardman JG, Limbird LE, Gilman AG: Goodman and Gilman's. The Pharmacological Basis of Therapeutics. 10th edition. New York, McGraw-Hill, 2001, pp 569-619

2. Baselt RC: Disposition of Toxic Drugs and Chemicals in Man. Sixth edition. Foster City, CA, Biomedical Publications, 2002

3. Porter WH, Moyer TP: Clinical toxicology. In Tietz Fundamentals of Clinical Chemistry. Fifth edition. Edited by CA Burtis, ER Ashwood, Philadelphia, WB Saunders Company, 2001, pp 636-679


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