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)
Drug |
Dose |
Route |
Indications |
Contraindications |
Atropine |
2 mg q5-10min prn Note: the Mark 1 kit contains 2 mg of atropine |
IV/IM/ETT |
Excessive muscarinic symptoms |
Relative - 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/IM |
Symptomatic nerve agent poisoning |
Rapid infusion may result in hypertension |
Diazepam (Valium) |
2-5 mg IV or 10 mg IM |
IV/IM |
Active seizures; administer as prophylaxis if moderate or severe signs of poisoning are present |
None |
*Adapted from Sidell. |
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Table 6. Summary of Treatment Modalities According to Severity of Exposure* (Open Table in a new window)
Severity/Route of Exposure |
Atropine |
2-PAM Cl |
Diazepam |
Other |
Suspected |
No |
No |
No |
Decontamination and 18-h observation for liquid exposures |
Mild |
2 mg for severe rhinorrhea or dyspnea; may repeat prn |
Administer if patient has nonimproving dyspnea or GI symptoms |
No |
Decontamination and 18-h observation for liquid exposures; oxygen |
Moderate |
6 mg; may require repeat doses |
Administer with atropine |
Administer even in absence of seizures |
Decontamination, oxygen |
Severe |
Start with 6 mg; may need to repeat |
Administer with atropine; should repeat once or twice |
Administer even in absence of seizures |
ABCs, decontamination |
*Adapted from Sidell. |
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Gases
Class Summary
All but the mildest exposures result in 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.
Anticholinergic
Class Summary
Antagonizes ACh at the muscarinic receptor.
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.
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.
Pralidoxime (2-PAM Cl, Protopam)
Reactivators of AChE.
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.
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.
Tables
Code Name |
Chemical Name |
VX |
O-Ethyl-S-[2(diisopropylamino)ethyl] methylphosphonothioate |
VE |
O-Ethyl-S-[2-(diethylamino)ethyl] ethylphosphonothioate |
VG |
O,O-Diethyl-S-[2-(diethylamino)ethyl] phosphorothioate |
VM |
O-Ethyl-S-[2-(diethylamino)ethyl] methylphosphonothioate |
V-gas |
Russian equivalent of VX |
Agent |
LCt50 (mg ⋅ min/m3) |
LD50 (mg) |
Aging Half-Life |
Tabun (GA) |
400 |
1000 |
46 h |
Sarin (GB) |
100 |
1700 |
5.2-12 h |
Soman (GD) |
50 |
100 |
40 sec to 10 min |
VX |
10 |
10 |
50-60 h |
Receptor Involved |
Clinical 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. [10] |
|
Severity of Exposure |
Signs and Symptoms - Liquid |
Signs and Symptoms - Vapor |
Onset of symptoms |
Possibly delayed toxicity |
Rapidly manifesting toxicity |
Minimal |
Localized sweating at site Localized fasciculations at site |
Miosis Rhinorrhea Mild dyspnea |
Moderate |
Fasciculations Diaphoresis Nausea, vomiting, and diarrhea Generalized weakness |
Above symptoms and the following: Moderate-to-marked dyspnea (bronchorrhea and/or bronchoconstriction) |
Severe |
Above 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 |
Drug |
Dose |
Route |
Indications |
Contraindications |
Atropine |
2 mg q5-10min prn Note: the Mark 1 kit contains 2 mg of atropine |
IV/IM/ETT |
Excessive muscarinic symptoms |
Relative - 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/IM |
Symptomatic nerve agent poisoning |
Rapid infusion may result in hypertension |
Diazepam (Valium) |
2-5 mg IV or 10 mg IM |
IV/IM |
Active seizures; administer as prophylaxis if moderate or severe signs of poisoning are present |
None |
*Adapted from Sidell. |
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Severity/Route of Exposure |
Atropine |
2-PAM Cl |
Diazepam |
Other |
Suspected |
No |
No |
No |
Decontamination and 18-h observation for liquid exposures |
Mild |
2 mg for severe rhinorrhea or dyspnea; may repeat prn |
Administer if patient has nonimproving dyspnea or GI symptoms |
No |
Decontamination and 18-h observation for liquid exposures; oxygen |
Moderate |
6 mg; may require repeat doses |
Administer with atropine |
Administer even in absence of seizures |
Decontamination, oxygen |
Severe |
Start with 6 mg; may need to repeat |
Administer with atropine; should repeat once or twice |
Administer even in absence of seizures |
ABCs, decontamination |
*Adapted from Sidell. |
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