Opioids/Benzodiazepines Poisoning Workup
- Author: Christopher P Holstege, MD; Chief Editor: Zygmunt F Dembek, PhD, MPH, MS, LHD more...
The use of laboratory studies in the treatment of patients potentially exposed to opioid or benzodiazepine incapacitating agents should initially focus on the potential complications associated with those sedatives. Additional laboratory tests can also be conducted in an attempt to identify the diagnosis of the incapacitating agent if the specific agent is unknown to the clinicians.
Rapid urine drug screenings (immunoassays) are available and may assist health care professionals in making a diagnosis. However, these immunoassays do have a number of limitations. Opioid immunoassays are directed toward morphine. Many synthetic opioids, such as fentanyl, show no cross-reactivity with these assays. Testing for benzodiazepines is complicated because numerous benzodiazepines have substantially different structures. Results may be positive for diazepam, but negative for other benzodiazepines (eg, clonazepam).
Performing a complete blood count, electrolyte tests, clotting studies, and renal and liver function tests is reasonable in any person who has potentially been exposed to an incapacitating agent.
If the patient is comatose, performing a urine myoglobin and/or creatine phosphokinase test is warranted to exclude rhabdomyolysis. Hyperkalemia, hyperphosphatemia, and hypocalcemia may occur in association with rhabdomyolysis. The lactate level may also be elevated in these patients.
If the incapacitating agent is unknown, obtain extra blood and urine samples. Subsequent testing can be performed to confirm the causative agent.
See the list below:
A patient who has potentially been exposed to an opioid or a benzodiazepine incapacitating agent and who is comatose may be at risk for aspiration pneumonia. Obtain a chest radiograph.
If the etiology of a patient's altered mental status is uncertain, performing a head CT scan to exclude other intracranial processes is reasonable.
Both opioids and benzodiazepines may be associated with bradycardia. However, stress occurring in response to a situation associated with an exposure to aerosolized opioids or benzodiazepines may lead to tachycardia. Patients who are exposed to these agents and have preexisting cardiac disease may be at risk for cardiac ischemia. Perform an ECG to exclude these potential problems.
Stone A. Chemical weapons. U.S. research on sedatives in combat sets off alarms. Science. 2002 Aug 2. 297(5582):764. [Medline].
Riches JR, Read RW, Black RM, Cooper NJ, Timperley CM. Analysis of clothing and urine from Moscow theatre siege casualties reveals carfentanil and remifentanil use. J Anal Toxicol. 2012 Nov-Dec. 36:647-656. [Medline].
Chan S. Lethal Moscow Gas An Opiate?. CBS. October 29, 2002. Available at http://www.cbsnews.com/news/lethal-moscow-gas-an-opiate/.
Fallahinejad Ghajari M, Ansari G, Soleymani AA, Shayeghi S, Fotuhi Ardakani F. Comparison of Oral and Intranasal Midazolam/Ketamine Sedation in 3-6-year-old Uncooperative Dental Patients. J Dent Res Dent Clin Dent Prospects. 2015 Spring. 9 (2):61-5. [Medline].
Siegel RA, Kapoor M, Cheryala N, Georg GI, Cloyd JC. Water-soluble benzodiazepine prodrug/enzyme combinations for intranasal rescue therapies. Epilepsy Behav. 2015 Aug. 49:347-50. [Medline].
Hess L, Schreiberova J, Fusek J. Pharmacological non-lethal weapons. 3rd European Symposium on Non-Lethal Weapons. May 10-12, 2005. Available at http://www.non-lethal-weapons.com/sy03abstracts/V23.pdf. Accessed: August 18, 2015.
Xi LY, Zheng WM, Zhen SM, Xian NS. Rapid arrest of seizures with an inhalation aerosol containing diazepam. Epilepsia. 1994 Mar-Apr. 35(2):356-8. [Medline].
Booij LH. [The agent used to free the hostages in Moscow and the insufficient Dutch preparations in case of a terrorist chemical disaster]. Ned Tijdschr Geneeskd. 2002 Dec 14. 146(50):2396-401. [Medline].
Brooks M. Knockout gas: Chemical weapons in disguise?. New Scientist. October 2007. [Full Text].
Coupland RM. Incapacitating chemical weapons: a year after the Moscow theatre siege. Lancet. 2003 Oct 25. 362(9393):1346. [Medline].
Dando M. Biologists napping while work militarized. Nature. 2009 Aug 20. 460(7258):950-1. [Medline].
Enserink M, Stone R. Toxicology. Questions swirl over knockout gas used in hostage crisis. Science. 2002 Nov 8. 298(5596):1150-1. [Medline].
Gudmundsdottir H, Sigurjonsdottir JF, Masson M, et al. Intranasal administration of midazolam in a cyclodextrin based formulation: bioavailability and clinical evaluation in humans. Pharmazie. 2001 Dec. 56(12):963-6. [Medline].
Hung OR, Whynot SC, Varvel JR, et al. Pharmacokinetics of inhaled liposome-encapsulated fentanyl. Anesthesiology. 1995 Aug. 83(2):277-84. [Medline].
Ljungman G, Kreuger A, Andreasson S, et al. Midazolam nasal spray reduces procedural anxiety in children. Pediatrics. 2000 Jan. 105(1 Pt 1):73-8. [Medline].
Loftsson T, Gudmundsdottir H, Sigurjonsdottir JF, et al. Cyclodextrin solubilization of benzodiazepines: formulation of midazolam nasal spray. Int J Pharm. 2001 Jan 5. 212(1):29-40. [Medline].
Mather LE, Woodhouse A, Ward ME. Pulmonary administration of aerosolised fentanyl: pharmacokinetic analysis of systemic delivery. Br J Clin Pharmacol. 1998 Jul. 46(1):37-43. [Medline].
Rieder J, Keller C, Hoffmann G. Moscow theatre siege and anaesthetic drugs. Lancet. 2003 Mar 29. 361(9363):1131. [Medline].
Schiermeier Q. Hostage deaths put gas weapons in spotlight. Nature. 2002 Nov 7. 420(6911):7. [Medline].
Wax PM, Becker CE, Curry SC. Unexpected "gas" casualties in Moscow: a medical toxicology perspective. Ann Emerg Med. 2003 May. 41(5):700-5. [Medline].
Worsley MH, MacLeod AD, Brodie MJ, et al. Inhaled fentanyl as a method of analgesia. Anaesthesia. 1990 Jun. 45(6):449-51. [Medline].