CBRNE - Nerve Agents, V-series - Ve, Vg, Vm, Vx Medication

  • Author: Daniel C Keyes, MD, MPH; Chief Editor: Robert G Darling, MD, FACEP   more...
 
Updated: Mar 16, 2010
 

Medication Summary

Table 5 summarizes different agents used to treat nerve agent–poisoned patients. Table 6 provides an overview of general treatment guidelines.

Table 5. Drugs Used to Treat Nerve Agent–Poisoned Patients* (Open Table in a new window)

DrugDoseRouteIndicationsContraindications
Atropine2 mg q5-10min prn



Note: the Mark 1 kit contains 2 mg of atropine



IV/IM/ETTExcessive muscarinic symptomsRelative - IV route in hypoxia has been associated with ventricular fibrillation
2-PAM Cl (pralidoxime chloride, Protopam)15-25 mg/kg over 20 min; can be repeated after 1 h



Note: The Mark 1 kit contains 600 mg of pralidoxime.



IV/IMSymptomatic nerve agent poisoningRapid infusion may result in hypertension
Diazepam (Valium)2-5 mg IV or 10 mg IMIV/IMActive seizures; administer as prophylaxis if moderate or severe signs of poisoning are presentNone
*Adapted from Sidell.

Table 6. Summary of Treatment Modalities According to Severity of Exposure* (Open Table in a new window)

Severity/Route of ExposureAtropine2-PAM ClDiazepamOther
SuspectedNoNoNoDecontamination and 18-h observation for liquid exposures
Mild2 mg for severe rhinorrhea or dyspnea; may repeat prnAdminister if patient has nonimproving dyspnea or GI symptomsNoDecontamination and 18-h observation for liquid exposures; oxygen
Moderate6 mg; may require repeat dosesAdminister with atropineAdminister even in absence of seizuresDecontamination, oxygen
SevereStart with 6 mg; may need to repeatAdminister with atropine; should repeat once or twiceAdminister even in absence of seizuresABCs, decontamination
*Adapted from Sidell.
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Gases

Class Summary

All but the mildest exposures have some degree of respiratory compromise. For this reason, oxygen should be readily available. Most of these symptoms result from bronchorrhea and bronchoconstriction and improve after administration of antidotes, especially atropine. In the severely poisoned patient, respiratory muscle paralysis adds to the problem. Intubation and mechanical ventilation are required for these patients.

Oxygen

 

Assists patients with respiratory compromise.

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Anticholinergic

Class Summary

Antagonizes ACh at the muscarinic receptor.

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Atropine IV/IM (Isopto, Atropair, Atropisol)

 

Antagonizes ACh at its receptor; acts only at muscarinic receptor, leaving nicotinic receptors unaffected; in contrast to organophosphate insecticides, nerve agents rarely require >20 mg; administer until excess muscarinic symptoms improve; this can be gauged by improved ease of breathing in conscious patient or improvement in ease of ventilation of intubated patient; airway patency is critical, life-saving endpoint in treatment.

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Oximes

Class Summary

Reactivators of AChE; 2-PAM Cl, also known as pralidoxime, is widely available in the US; administer concomitantly with atropine. After aging (irreversible binding of agent with AChE enzyme) occurs, usefulness of pralidoxime is negligible. VX has a slow aging process (aging half-life has been calculated at 48 h or more), so delayed treatment with oximes is considered beneficial. Pralidoxime has a half-life of 1 hour. Pralidoxime and TMB-4 have similar characteristics and are widely used outside of the US.

Another subset of oximes termed the H oximes (H is for Hagedorn) include agents such as HI-6, HGG-12, and HGG-42; studies exist using these antidotes in the military setting, but the drugs currently are not widely available for use in the US.

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Pralidoxime (2-PAM Cl, Protopam)

 

Reactivators of AChE.

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Benzodiazepines

Class Summary

Seizures can result from severe nerve agent poisoning; for this reason, treatment with benzodiazepines has been advocated as part of the antidotal armamentarium. Experts advocate use in moderately-to-severely poisoned patients, even prior to seizure onset, as well as in actively seizing patients.

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Diazepam (Valium, Diazemuls)

 

Belongs to benzodiazepine family, the members of which act by stimulating GABA, the main Inhibitory neurotransmitter in the CNS. Stimulation of GABA results in sedation and increased seizure threshold. The military has a 10-mg autoinjector form available, known as the CANA kit. Unlike the atropine and pralidoxime autoinjectors, this device is not used for self-administration.

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Contributor Information and Disclosures
Author

Daniel C Keyes, MD, MPH  Vice Chair, Academic Affairs, Department of Emergency Medicine, John Peter Smith Health Network; Clinical Associate Professor, Department of Surgery, Division of Emergency Medicine and Toxicology, University of Texas Southwestern School of Medicine

Daniel C Keyes, MD, MPH is a member of the following medical societies: American College of Emergency Physicians, American College of Medical Toxicology, American College of Occupational and Environmental Medicine, and American College of Physicians-American Society of Internal Medicine

Disclosure: Nothing to disclose.

Coauthor(s)

Fernando L Benitez, MD  Assistant Medical Director, Dallas Metropolitan BioTel (EMS) System; Associate Professor in Emergency Medicine, Department of Surgery, Division of Emergency Medicine, University of Texas Southwestern Medical Center and Parkland Health and Hospital

Fernando L Benitez, MD is a member of the following medical societies: American College of Emergency Physicians, American Medical Association, and National Association of EMS Physicians

Disclosure: Nothing to disclose.

Larissa I Velez-Daubon, MD  Associate Professor, Associate Program Director, Department of Surgery, Division of Emergency Medicine, University of Texas Southwestern Medical School, Parkland Memorial Hospital; Associate Program Director and Staff Toxicologist, Department of Surgery, Division of Emergency Medicine, North Texas Poison Center, Parkland Memorial Hospital

Larissa I Velez-Daubon, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Emergency Physicians, American College of Medical Toxicology, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Specialty Editor Board

Fred Henretig, MD  Director, Section of Clinical Toxicology, Professor, Medical Director, Delaware Valley Regional Poison Control Center, Departments of Emergency Medicine and Pediatrics, University of Pennsylvania School of Medicine, Children's Hospital

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD  Senior Pharmacy Editor, eMedicine

Disclosure: eMedicine Salary Employment

Rick Kulkarni, MD 

Rick Kulkarni, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine

Disclosure: WebMD Salary Employment

John D Halamka, MD, MS  Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center

John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Chief Editor

Robert G Darling, MD, FACEP  Adjunct Clinical Assistant Professor of Military and Emergency Medicine, Uniformed Services University of the Health Sciences, F Edward Hebert School of Medicine; Associate Director, Center for Disaster and Humanitarian Assistance Medicine

Robert G Darling, MD, FACEP is a member of the following medical societies: American College of Emergency Physicians, American Medical Association, American Telemedicine Association, and Association of Military Surgeons of the US

Disclosure: Nothing to disclose.

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Chemical Terrorism Agents and Syndromes. Signs and symptoms. Chart courtesy of North Carolina Statewide Program for Infection Control and Epidemiology (SPICE), copyright University of North Carolina at Chapel Hill, www.unc.edu/depts/spice/chemical.html.
Table 1. Code and Chemical Names for the V-Series Agents
Code NameChemical Name
VXO-Ethyl-S-[2(diisopropylamino)ethyl] methylphosphonothioate
VEO-Ethyl-S-[2-(diethylamino)ethyl] ethylphosphonothioate
VGO,O-Diethyl-S-[2-(diethylamino)ethyl] phosphorothioate
VMO-Ethyl-S-[2-(diethylamino)ethyl] methylphosphonothioate
V-gasRussian equivalent of VX
Table 2
AgentLCt50 (mg·min/m3)LD50 (mg)Aging Half-Life
Tabun (GA)400100046 h
Sarin (GB)10017005.2-12 h
Soman (GD)5010040 sec to 10 min
VX101050-60 h
Table 3. Pharmacologic Effects of Nerve Agents*
Receptor InvolvedClinical Effect
Acetylcholine, GABA, N -methyl-D -aspartate: Central (CNS)Anxiety, restlessness, seizures, failure to concentrate, depression, coma, apnea
Acetylcholine: Muscarinic



Postganglionic parasympathetic



"DUMBELS" (commonly used mnemonic)



D - Diarrhea



U - Urination



M - Miosis



B - Bronchorrhea, bronchoconstriction



E - Emesis



L - Lacrimation



S - Salivation



Note: The other commonly used mnemonic "SLUDGE" is not used here, as it does not include an important sign and symptom: bronchorrhea and bronchoconstriction.



Acetylcholine: Nicotinic



Motor endplate



Sympathetic and parasympathetic ganglia



Pallor, tachycardia, hypertension, muscle weakness and/or paralysis, fasciculations



Note: Some use the days of the week as an easy mnemonic for these:



M - Mydriasis



T - Tachycardia



W - Weakness



tH - Hypertension



F - Fasciculations



* Adapted from Marrs, Maynard, and Sidell.[1]
Table 4. Severity of Toxicity from Liquid and Vapor Exposures
Severity of ExposureSigns and Symptoms - LiquidSigns and Symptoms - Vapor
Onset of symptomsPossibly delayed toxicityRapidly manifesting toxicity
MinimalLocalized sweating at site



Localized fasciculations at site



Miosis



Rhinorrhea



Mild dyspnea



ModerateFasciculations



Diaphoresis



Nausea, vomiting, and diarrhea



Generalized weakness



Above symptoms and the following:



Moderate-to-marked dyspnea (bronchorrhea and/or bronchoconstriction)



SevereAbove symptoms and the following:



Loss of consciousness



Seizures



Generalized fasciculations



Flaccid paralysis and apnea



Above symptoms and the following:



Loss of consciousness



Seizures



Generalized fasciculations



Flaccid paralysis and apnea



Table 5. Drugs Used to Treat Nerve Agent–Poisoned Patients*
DrugDoseRouteIndicationsContraindications
Atropine2 mg q5-10min prn



Note: the Mark 1 kit contains 2 mg of atropine



IV/IM/ETTExcessive muscarinic symptomsRelative - IV route in hypoxia has been associated with ventricular fibrillation
2-PAM Cl (pralidoxime chloride, Protopam)15-25 mg/kg over 20 min; can be repeated after 1 h



Note: The Mark 1 kit contains 600 mg of pralidoxime.



IV/IMSymptomatic nerve agent poisoningRapid infusion may result in hypertension
Diazepam (Valium)2-5 mg IV or 10 mg IMIV/IMActive seizures; administer as prophylaxis if moderate or severe signs of poisoning are presentNone
*Adapted from Sidell.
Table 6. Summary of Treatment Modalities According to Severity of Exposure*
Severity/Route of ExposureAtropine2-PAM ClDiazepamOther
SuspectedNoNoNoDecontamination and 18-h observation for liquid exposures
Mild2 mg for severe rhinorrhea or dyspnea; may repeat prnAdminister if patient has nonimproving dyspnea or GI symptomsNoDecontamination and 18-h observation for liquid exposures; oxygen
Moderate6 mg; may require repeat dosesAdminister with atropineAdminister even in absence of seizuresDecontamination, oxygen
SevereStart with 6 mg; may need to repeatAdminister with atropine; should repeat once or twiceAdminister even in absence of seizuresABCs, decontamination
*Adapted from Sidell.
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