Sorted By Test Name - Mayo Medical Laboratories

MSPR
500373
DPRP
505345
Reference Values:
Negative
EMIT cutoff concentration: 25 ng/mL
Positives are reported with a quantitative GC-MS result.
Clinical References: Baselt RC: In Disposition of Toxic Drugs and Chemicals in Man, 5th edition.
Chemical Toxicology Institute, Foster City, CA 2000
Drug of Abuse, Propoxyphene GC-MS Confirmation, Urine
Clinical Information: Propoxyphene (Darvon) is an analgesic used for the treatment of
mild-to-moderate pain that is not adequately relieved by aspirin. It is a congener of the narcotic
methadone but is classified as a non-narcotic. It produces analgesia by binding to u-opioid receptors in the
central nervous system (CNS). Propoxyphene undergoes hepatic N-demethylation to produce a major
metabolite, norpropoxyphene, which has one-fourth to one-half the pharmacologic activity of the parent
drug. The serum half-lives of propoxyphene and norpropoxyphene are 8 to 24 hours and 20 to 50 hours,
respectively. Rapid tissue binding of propoxyphene occurs, resulting in the immediate and almost
complete disappearance from the bloodstream and relatively high concentrations in the brain, lung, liver,
and kidney. Toxic manifestations are similar to those produced by codeine and include respiratory and
CNS depression, cardiac arrhythmias, pulmonary edema, hypotension, hallucinations, convulsions, and
coma. Accidental or intentional ingestion of large amounts of propoxyphene may cause death. Cardiac
toxicity from elevated blood levels may be indicated when urine concentrations for propoxyphene are
>10,000 ng/mL or norpropoxyphene is >30,000 ng/mL.
Useful For: Confirmation of propoxyphene usage. This test is designed for laboratories that perform
their own drug of abuse screening, but do not have confirmation facilities. The confirmation is performed
on urine only and should be ordered as the drug class to be confirmed.
Interpretation: A positive result derived by this testing indicates that the patient has used
propoxyphene in the recent past. Random urine collection results are not clinically definitive but the
following values may be used as guidelines: Propoxyphene -1,000 ng/mL to 5,000 ng/mL: typical for
therapeutic dosages ->10,000 ng/mL: may indicate toxic blood concentration ->80,000 ng/mL: may
indicate potentially lethal blood concentration Norpropoxyphene -2,000 ng/mL to 20,000 ng/mL: typical
for therapeutic dosages ->30,000 ng/mL: may indicate toxic blood concentration -> 80,000 ng/mL: may
indicate potentially lethal blood concentration
Reference Values:
Negative
Positives are reported with a quantitative GC-MS result.
Cutoff concentrations
Propoxyphene: