Fast Five Quiz: Cannabis Use and Abuse

Richard H. Sinert, DO


April 08, 2020

Urine immunoassays are used to detect a conjugated delta-9-tetrahydrocannanbinol (THC) metabolite, 11-nor-delta-9-THC carboxylic acid. Features of the test results are as follows:

  • After a single, acute use, THC is detectable in the urine for 7 days.

  • With chronic use, THC is detectable in the urine for 10-30 days.

  • Enzyme-multiplied immunoassay technique can detect urine levels as low as 20-100 ng/mL.

  • These screening tests correlate with prior exposure, not with the amount used or degree of clinical effect.

False-positive results can occur with ibuprofen, naproxen, dronabinol, efavirenz, and hemp seed oil. False-positive results are unlikely to result from use of health food store hemp products or from secondhand smoke inhalation, unless this exposure occurs in an unventilated space.

Treatment depends on the clinical presentation, the age of the patient, and the presence of other legal or illicit substances. Immediate management should be supportive, including cardiovascular and neurologic monitoring, and placement in a quiet room.

Gastric decontamination is rarely indicated, but may be considered in children younger than 16 years with a large ingestion less than 2 hours before presentation. Patients who are agitated, with psychosis, or with significant anxiety should be treated with benzodiazepines. Patients with an acute psychotic episode should also undergo substance abuse counseling. Patients who request counseling should be referred for treatment.

Maladaptive behaviors associated with cannabis are more common in males, younger adolescents, patients in urban settings, patients presenting to emergency departments after midnight or on weekends, and patients with psychiatric comorbidities. These patients should be referred to substance abuse counseling.

Read more about cannabis poisoning.

This Fast Five Quiz was excerpted and adapted from the Medscape Drugs & Diseases articles Cannabis-Related Disorders and Cannabinoid Poisoning.

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