Patients with chronic pain on opioid therapy taking dronabinol: Incidence of false negatives using radioimmunoassay

Sanjeet Narang, MD; Ajay D. Wasan, MD, MSc; Edgar L. Ross, MD; Edward Michna, MD; Jui-Yuan Chen, MD; Robert N. Jamison, PhD

doi:10.5055/jom.2008.0004

Authors

Sanjeet Narang, MD
Ajay D. Wasan, MD, MSc
Edgar L. Ross, MD
Edward Michna, MD
Jui-Yuan Chen, MD
Robert N. Jamison, PhD

DOI:

https://doi.org/10.5055/jom.2008.0004

Keywords:

chronic pain, marinol, dronabinol, cannabinoids, serum blood screening, radioimmunoassay, marijuana, opioids

Abstract

Background: Serum blood toxicology screens are believed to be important to monitor compliance and to identify levels of illicit substances in patients taking opioids for their chronic pain.
Methods: In this study, the authors examine the incidence of tetrahydrocannabinol (THC) in consecutive blood samples of patients given dronabinol. We assessed the incidence of THC in 27 patients who participated in a single-dose, double-blind crossover trial of dronabinol (Marinol® capsules), a synthetic Δ9-THC, as part of a larger study, to determine the reliability of the toxicology screening. Subjects were randomly administered 10 mg or 20 mg of dronabinol or placebo over the course of three 8-hour visits for a combined 228 serum blood samples. Levels of THC were quantified using radioimmunoassay.
Results: The majority of the samples (57.4 percent) showed presence of study drug as expected. However, 43 samples (42.6 percent) showed no detectable evidence of THC 4 and 8 hours after administration of dronabinol. Five subjects showed lower serum levels on the higher dose (20 mg) than on the lower dose (10 mg) after 4 hours, and two subjects showed lower levels with the higher dose after 8 hours. One subject had no detectable THC on any dose of dronabinol.
Conclusions: These toxicology reports point to higher than anticipated false-negative results with radioimmunoassay blood serum screening. Results could be explained by the lower sensitivity of this screening technique and also in how oral cannabinoids are metabolized. Further investigations are needed on the accuracy of the detection of THC among patients known to have used dronabinol.

Author Biographies

Sanjeet Narang, MD

Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts.

Ajay D. Wasan, MD, MSc

Departments Anesthesiology, Perioperative and Pain Medicine and Psychiatry, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts.

Edgar L. Ross, MD

Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts.

Edward Michna, MD

Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts.

Jui-Yuan Chen, MD

Department of Anesthesiology, Shin Kong Wu Ho-Su Memorial Hospital, Taiwan.

Robert N. Jamison, PhD

Departments Anesthesiology, Perioperative and Pain Medicine and Psychiatry, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts.

References

Michna E, Ross EL, Hynes WL, et al.: Predicting aberrant drug behavior in patients treated for chronic pain: Importance of abuse history. J Pain Symp Manage. 2004; 28: 250-258.

Michna E, Jamison RN, Pham LD, et al.: The utility of urine toxicology screening in monitoring opioid therapy adherence among chronic pain patients. Clin J Pain. 2007; 23: 173-179.

Substance Abuse and Mental Health Services Administration (SAMHSA): Results from the 2005 national survey on drug use and health: National findings. Available at www.oas.samhsa.gov. Accessed May 12, 2007.

Fishbain D, Rosomoff HL, Rosomoff RS: Drug Abuse, dependence, and addiction in chronic pain patients. Clin J Pain. 1992; 8: 77-85.

Ware MA, Doyle CR, Woods R, et al.: Cannabis use for chronic non-cancer pain: Results of a prospective survey. Pain. 2003; 102: 211-216.

Narang S, Gibson D, Wasan AD, et al.: Efficacy of dronabinol as an adjuvant treatment for chronic pain patients on opioid therapy. J Pain. 2008 (in press).

Cleeland C, Gonin R, Hatfiled AK, et al.: Pain and its treatment in outpatients with metastatic cancer. N Engl J Med. 1994; 330: 592-596.

Tan G, Jensen MP, Thornby JI, et al.: Validation of the brief pain inventory for chronic nonmalignant pain. J Pain. 2004; 5: 133-137.

Zigmond A, Snaith RP: The Hospital Anxiety and Depression Scale. Acta Psychia Scand. 1983; 67: 361-370.

Bjelland I, Dahl AA, Haug TT, et al.: The validity of the Hospital Anxiety and Depression Scale: An updated literature review. J Psychosom Res. 2002; 52: 69-77.

Moorey S, Greer S, Watson M, et al.: The factor structure and factor stability of the Hospital Anxiety and Depression Scale in patients with cancer. Br J Psychia. 1991; 58: 255-259.

Cook CE, Seltzman HH, Schindler VH, et al.: Radioimmunoassays for cannabinoids. NIDA Res Monogr. 1982; 42: 19-32.

Yamamoto I, Watanabe K, Narimatsu S, et al.: Recent advances in the metabolism of cannabinoids. Intern J Biochem Cell Bio. 1995; 27: 741-746.

Manno J, Manno BR, Kemp PM, et al.: Temporal indication of marijuana use can be extimated from plasma and urine concentrations of delta9-tetrahydroconnabinal, 11-hydoxy-delta9-tetrahydrocannabinal, and 11-nor-delta9-tetrahydrocannabinal-9-carboxylic acid. J Anal Toxicol. 2001; 25: 538-549.

Goodwin R, Gustafson RA, Barnes A, et al.: Delta9-tetrahydrocannabinal, 11-hydroxy-delta9-tetrahydrocannabinol and 11-nor-9-carboxy-delta9-tetrahydrocannabinol in human plasma after controlling oral administration of cannabinoids. Ther Drug Monit. 2006; 28: 545-551.

Cone E, Huestis MA: Related blood concentrations of tetrahydrocannabinol and metabolites to pharmacologic effects and time of marijuana usage. Ther Drug Monit. 1993; 15: 527-532.