Consult with a medical toxicologist or a poison center at the national toll-free number 1-800-222-1222 for further guidance on appropriate antidote dosing. Currently two atropine/pralidoxime autoinjector formulations exist:
Mark 1 Kit - each kit contains one 600 mg pralidoxime autoinjector, one 2 mg atropine autoinjector
Duodote - a single autoinjector contains approximately 600 mg of pralidoxime and 2 mg of atropine
In general treatment of severe nerve agent poisoning requires lower total doses of atropine than required for treatment of organophosphorous compounds
In severe cases of nerve agent toxicity following vapor exposure (i.e. apneic and unconscious) it may take up to 15 mg of atropine to restore consciousness and breathing. Typically atropine has not been required for more than 3 hours to treat the life threatening effects. Non - life threatening effects such as nausea and vomiting have required atropine for 6-36 hours.
Organophosphate ingestions have required hundreds of mgs a day of atropine
Mild effects:
Miosis alone (no respiratory symptoms)- No antidotes. However, if eye/head pain or N&V (in the absence of other systemic signs suggesting a liquid exposure) are severe use atropine ophthalmic drops
0.05 mg/kg given IM or via autoinjector (0.25 and 0.50 mg sizes are available)
Child (3-7 yrs)
1 mg autoinjector/IM
Child (8-14 yrs)
2 mg autoinjector/IM
Adolescent/Adult
2 mg autoinjector/IM
Pregnant women
2 mg autoinjector/IM
Senior
1 mg autoinjector/IM
Mild/Moderate effects:
These include localized swelling, muscle fasciculations, nausea and vomiting, weakness, shortness of breath. Utilize auto-injectors if available. May use a 600 mg 2PAM Cl auto-injector in an infant as small as 12 kg.
Repeat initial dose (2 mg max) of atropine via autoinjector (preferable) or IM every 5 - 10 minutes until dyspnea, resistance to ventilation, and secretions are minimized.
If resistance to ventilation is significant , requiring repeat dosing in less than 5 minutes utilize the higher doses and increase frequency depicted in the severe effects section below
Treat vomiting and diarrhea from a liquid exposure in a similar way.
Regular IM atropine dosing may take 20-25 minutes to have a therapeutic effect (vs. 8 minutes with an autoinjector).
May repeat pralidoxime - up to a total of 45 mg/kg during the first hour
May repeat pralidoxime - up to 45 mg/kg 1 hour after initial treatment
Severe Effects - Initial Dosing:
These include unconsciousness, convulsions, apnea, flaccid paralysis and requiring assisted ventilation (severe respiratory distress). I.V. atropine has produced ventricular fibrillation in hypoxic animals with nerve agent poisoning. Therefore it is recommended that hypoxia be corrected prior to atropine administration. However atropine should not be withheld due to fears of this complication. It would be preferable to utilize an atropine autoinjector for the first dose in the hypoxic nerve agent exposed patient.
Repeat atropine 2 mg via autoinjector (preferable) or IM (child 8-14, adolescents, adults, pregnant women, and seniors), 0.05 mg/kg (0.25 mg - 0.50 mg) (infant 0-3) and 1 mg (child 3-7) at 2 -5 minute intervals until secretions have diminished, breathing is comfortable, and airway resistance has returned to normal.
Diazepam or midazolam should be given to all patients having seizure activity, unconsciousness, diffuse muscle twitching, and if >1 organ is involved. The military gives diazepam as part of initial therapy for any seriously ill NA exposed patients. Utilized early, atropine may function as an anticonvulsant. The benzodiazepines are the most effective seizure medication for nerve agent toxicity.
If available, IV administration of diazepam is the preferable route for treatment of seizures.
