Intoxication,Drugs of Abuse Testing & Forensics A Part 2

by: Nachman Brautbar
"Intoxication, Drugs of Abuse Testing
& Forensics Application
By Nachman Brautbar, M.D.

What is interesting in these studies, is that in 14 cases, the DRE entirely missed the drugs found in urine, and in 47 of the specimens for which the laboratory confirmed multiple substances, the DRE decisions were combinations of hits, false positives and false negatives. The DRE missed marijuana more often than other drug categories, but it cannot be determined whether the misses were DRE error or a consequence of the drugs' time course. Since the drugs principal metabolite can be detected in urine for days to weeks, a specimen may test positive even though it was obtained at a time when active marijuana was not present. A marijuana positive in urine which is not supported with evidence of behavioral impairment, cannot and does not speak to the question of drug Aintoxication@. This scientific fact is commonly, and for some reason, forgotten or is unknown to some forensic physicians who have the professional and ethical responsibility to evaluate whether the patient was under the influence of illicit drugs. For instance, on one occasion, I remember a patient who was involved in a truck collision while on the job, and his urine tested positive for marijuana. The forensic examiner opined that the patient was Aunder the influence@, despite the fact that the emergency room notes and the paramedic notes clearly stated the patient was alert x 4. As a matter of fact, in the study of DRE quoted above cocaine misses occurred with the second highest frequency. Behavioral science show that stimulants are often difficult to detect, but it cannot be determined with certainty whether the misses are true errors. Since the half-life of cocaine effects is approximately 90 minutes, and the metabolite (breakdown products of cocaine) benzoylecgonine (BE) is known to have no psychoactive effect and can be detected for 24 or 48 hours (usually), urine positive for BE does not mean that the suspect was Aunder the influence@ during the evaluation.

The Clear Message from these Studies is

The presence of drugs of abuse in the urine cannot be used for the Aintoxication defense.
The presence of drugs of abuse in the blood cannot automatically be extrapolated to the Aintoxication defense. Each case requires careful analysis of the medical records and the clinical reliability of the blood levels.
The presence of drugs of abuse in hair has no meaning whatsoever and cannot support the Aintoxication defense. The only extrapolation to be made is that drugs were used sometime in the past.
Medications and Substances Causing False Positives
There are 161 prescription and over-the-counter medications which have been studied and show that 65 of them produce false positive results in the commonly administered urine test for drugs. Siegel, according to the Los Angeles Times report, (a psychopharmacologist at UCLA), said ""The widespread testing and reliance of tale-tale traces of drugs in the urine is simply a panic reaction invoked, because the normal techniques for controlling drug use have not worked very well. The next epidemic will be testing abuse."" The most commonly used urine testing methodology is AMIV, has been shown that over 250 over-the-counter medications and prescription drug interactions can cause false positive testing using this methodology. The following have been reported as causing false positive tests are shown in the next table.

TABLE 1: Medications/Substances Causing False Positives/Cross-Reactions (Preliminary Testing)

Marijuana
Pain relievers such as Advil, Nuprin, Motrin and menstrual cramp medications like Midol and Trendar. All drugs containing Ibuprofen. Passive marijuana smoking. It has been described that passive marijuana inhalation at a rock concert can test positive in the urine despite the fact that the person has not been using marijuana.

Amphetamines
Dristan Nasal Spray, Neosynephren, Vicks Nasal Spray, Sudafed, and others containing ephedrine or pnenypropanolamine.

Opiates
Vicks Formula 44M containing Dextromethorphan, and Primatene-M containing perylamine, as well as the pain reliever Demerol and prescription anti-depressant Elavil, and even Quinine Water

Methadone
NyQuil Nighttime Cold Medicine

Cocaine
Antibiotics such as Ampicillin and Amoxicillin.

PCP
Diazepam, as well as some ingredients in cough medicines, Dextromethorphan.

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