Correspondence

Testing Reckless Drivers for Substance Abuse

N Engl J Med 1995; 332:892-893March 30, 1995

Article

To the Editor:

The urine tests used by Brookoff et al. (Aug. 25 issue)1 detected neither cocaine nor the active component of marijuana, delta-9-tetrahydrocannabinol, but did detect their metabolites, benzoylecgonine and COOH-delta-9-tetrahydrocannabinol. Urine tests for cocaine and marijuana have been designed specifically to recognize the metabolites rather than the parent compounds, because the metabolites can be detected longer after drug use, thus increasing the sensitivity of the test for detecting any abuse. Neither metabolite is psychoactive,2,3 but both may be detected for at least one to three days after occasional use, at times when parent-drug levels and impairment have become undetectable.2-4 And, as the authors note, these metabolites can be detected for much longer periods after long-term use.1-4 The conjunction of reckless driving and a positive urine test for cocaine or marijuana may suggest a high probability of concurrent drug intoxication. But the positive test establishes only previous drug use, not the presence of an intoxicating drug at the time of the specimen collection.

Petrie M. Rainey, M.D., Ph.D.
Yale University School of Medicine, New Haven, CT 06520

4 References

1. 1

   Brookoff D, Cook CS, Williams C, Mann CS. Testing reckless drivers for cocaine and marijuana. N Engl J Med 1994;331:518-522
   Full Text | Web of Science | Medline

2. 2

   Chang CN, Hawks RL. Implications of drug levels in body fluids: basic concepts. NIDA Res Monogr 1986;73:62-83
   Medline

3. 3

   Critical issues in urinalysis of abused substances; report of the Substance-Abuse Testing Committee. Clin Chem 1988;34:605-632
   Web of Science | Medline

4. 4

   Hawks RI, Chang CN. Examples of specific drug assays. NIDA Res Monogr 1986;73:84-112
   Medline

Author/Editor Response

The authors reply:

To the Editor: The presence of benzoylecgonine or COOH-delta-9-tetrahydrocannabinol in the urine has been accepted by both the scientific and legal communities as a specific sign of cocaine or marijuana use, respectively.1 A proportion of these metabolites may persist in the urine for more than one day after drug use. Therefore, the tests that we used were set at thresholds that correlated with recent use of the drug.2 We found that the majority of subjects who tested positive for these metabolites admitted to using the parent drug within 12 hours, underscoring the fact that these tests were accurate indicators of recent drug use.3 Our finding that most subjects who used marijuana admitted on the pretest interview to driving under its influence reinforced our concern about the seriousness of marijuana use.

Daniel Brookoff, M.D., Ph.D
Methodist Hospital, Memphis, TN 38104

Charles Williams, Ph.D.
University of Memphis, Memphis, TN 38134

3 References

1. 1

   Evans DG. Drug testing law, technology and practice. Deerfield, Ill.: Clark, Boardman & Callaghan, 1990.
   

2. 2

   National Institute on Drug Abuse. Mandatory guidelines for federal workplace drug testing programs. Fed Regist 1988;53:970-989
   

3. 3

   Brookoff D, Cook CS, Williams C, Mann CS. Testing reckless drivers for cocaine and marijuana. N Engl J Med 1994;331:518-522
   Full Text | Web of Science | Medline

Citing Articles (1)

Citing Articles

1. 1

   Claire Thorne, Marie-Louise Newell, David Dunn, Catherine Peckham, . (1995) The European Collaborative Study: clinical and immunological characteristics of HIV 1-infected pregnant women. BJOG: An International Journal of Obstetrics and Gynaecology 102:11, 869-875
   CrossRef