CBRNE - Opioids/Benzodiazepines Poisoning Medication

Updated: Oct 21, 2021
  • Author: Christopher P Holstege, MD; Chief Editor: Zygmunt F Dembek, PhD, MS, MPH, LHD  more...
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Medication Summary

If patients present after being exposed to aerosolized opioids or benzodiazepines, administration of the competitive antagonists naloxone and flumazenil, respectively, may be considered to reverse respiratory depression and coma.


Opioid Antagonists

Class Summary

Opioid antagonists competitively inhibit the binding of opioid agonists to the opioid receptors. The goal of this therapy is reinstitution of adequate spontaneous ventilation. In patients presenting with sedation of unknown etiology, the cautious administration of naloxone may be both diagnostic and therapeutic. Even in high doses, naloxone has an excellent safety profile.

Naloxone (Zimhi)

Historically, the most commonly used opioid receptor antagonist in the United States. It is used to reverse opioid intoxication or overdose. Prevents or reverses opioid effects (hypotension, respiratory depression, sedation), possibly by displacing opiates from their receptors. Half-life is 1 h. The injectable solution is available as a generic in vials and syringes (0.4 mg/mL, 1 mg/mL) for IV/IM/SC administration. A high-dose (5 mg/0.5 mL; Zimhi) IM/SC injectable solution in a prefilled syringe is also available. In pharmacokinetic studies, a single IM dose of 5-mg provided significantly higher peak plasma concentration and AUC compared with a single 2-mg IM injection.

Naloxone intranasal (Kloxxado, Narcan Nasal Spray)

Competitive opioid antagonist that antagonizes opioid effects by competing for the same receptor sites. The intranasal form is indicated for the emergency treatment of known or suspected opioid overdose, as manifested by respiratory and/or central nervous system depression. 


Benzodiazepine antagonists

Class Summary

Flumazenil is a competitive benzodiazepine antagonist that reverses the effects of benzodiazepines. However, benzodiazepine antagonists must be used with caution because if given to a patient chronically exposed to benzodiazepines, the antagonist can precipitate benzodiazepine withdrawal. If a patient receives flumazenil and goes into withdrawal, seizures or status epilepticus can occur, necessitating treatment with a non-benzodiazepine agent such as a barbiturate. Flumazenil is not recommended for indiscriminate use before a complete evaluation. If patients present with coma following aerosolized benzodiazepines exposure, flumazenil may be considered if the patient has respiratory depression and no history of long-term benzodiazepine use or seizure disorder. Use of flumazenil as a diagnostic and therapeutic agent for unsubstantiated drug-associated coma is controversial. A positive response to small titratable doses of flumazenil or other benzodiazepine antagonist may obviate the need for endotracheal (ET) intubation in the setting of benzodiazepine toxicity.

Flumazenil (Romazicon)

Reverses effects of benzodiazepines in overdose by selectively antagonizing benzodiazepine receptor at GABA-A complex.