The median lethal dose of VX for humans is approximately 6 to 10 milligrams by dermal exposure. Absorption is rapid (seconds to minutes) by inhalation but is significantly slower (minutes to hours) by dermal exposure. V-series nerve agents are odorless and tasteless. Biologic half-lives of V-series agents in humans are dependent on the dose administered as well as numerous other factors. 

The only use of V-series nerve agents (other than for research) is a chemical weapon. Thus, patients exposed to these agents may present in large numbers and report a history consistent with a terrorist attack. Symptoms are identical to those of the organophosphate toxidrome and include seizures, salivation, rhinorrhea, lacrimation, urination, diaphoresis, diarrhea, vomiting, miosis, and muscles spasms. Other symptoms include bronchospasm, central apnea, and bradycardia. Most deaths occur because of respiratory failure from the combination of respiratory symptoms. Those who survive nerve agent exposure may experience insomnia, depression, anxiety, irritability, and impaired memory and judgment. Ocular symptoms such as miosis, dim vision, blurry vision, and eye pain may persist for several weeks following exposure. Long-term neurologic effects of nerve agents have been reported.[2]

Exposure to V-series nerve agents should be considered if there is a clinical history concerning for exposure to nerve agents or symptoms of nerve agent exposure. Decontamination and treatment should begin as soon as possible. Laboratory tests for the presence of V-series agents in the body are not readily available and are not used to guide management. Patients may demonstrate lab abnormalities consistent with metabolic acidosis and the breakdown of striated muscle. Decreased erythrocyte cholinesterase levels may be observed after exposure to nerve agents. V-series nerve agents can also be detected in patients or in the environment by M8 paper, M9 tape, the M256A1 Chemical Agent Detector Kit, or the Joint Chemical Agent Detector (JCAD). [4][5][6][7][8][9]

The most important treatment is to terminate the patient's exposure by removing them from the contaminated environment and performing decontamination. Decontamination of the patient should always be performed before further medical treatment if possible. Some nerve agents may remain in the skin and continue to cause symptoms via a depot effect. Patients can be decontaminated by washing the affected areas with a 0.5% hypochlorite solution or with soap and clean water. However, the most effective method of decontamination of patients exposed to nerve agents is Reactive Skin Decontamination Lotion (RSDL), which should be used if available. The ingredients of Reactive Skin Decontamination Lotion sequester, retain, and neutralize organophosphate chemical warfare agents. Patients with large areas of dermal exposure will require numerous Reactive Skin Decontamination Lotion sponges to be effectively decontaminated.

Patients known to have been exposed to nerve agents or those exhibiting symptoms of nerve agent exposure should be given the antidote medications atropine and pralidoxime. Atropine works by binding and blocking muscarinic acetylcholine receptors, thus preventing the buildup of acetylcholine from continuing to affect the receptors. Because atropine does not act on nicotinic receptors, it will not improve skeletal muscle symptoms. Atropine should be administered until there is clinically evident reduction of airway secretions and airway resistance; doses of atropine can be given every three to five minutes. When administered soon after exposure to nerve agents, pralidoxime (also known as 2-pyridine aldoxime methyl chloride or 2-PAM Cl) removes the phosphyl moiety from acetylcholinesterase, thus reactivating the enzyme. Dual-chamber auto-injectors have been developed containing atropine sulfate and pralidoxime; examples of these include the Mark I Nerve Agent Antidote Kit (NAAK) or the newer Antidote Treatment Nerve Agent Autoinjector (ATNAA). Each Antidote Treatment Nerve Agent Autoinjector contains 2.1 mg of atropine and 600mg of pralidoxime.

Patients are also given diazepam or midazolam to prevent seizures and convulsions. When given intramuscularly, midazolam is absorbed faster than diazepam. The United States military uses a specialized diazepam auto-injector called the Convulsive Antidote Nerve Agent (CANA). Patients may be given up to three Antidote Treatment Nerve Agent Autoinjector autoinjectors. After three Antidote Treatment Nerve Agent Autoinjectors have been given, patients may receive additional doses of atropine every three to five minutes as clinically indicated, however additional doses of pralidoxime should not be given for 60 to 90 minutes. Patients who receive three Antidote Treatment Nerve Agent Autoinjector autoinjectors should also receive a Convulsive Antidote Nerve Agent (or a dose of benzodiazepine) even if there is no visible evidence of seizures. Medication administration by autoinjector has been shown to cause plasma concentrations of these medications to each therapeutic levels faster than intramuscular administration using a needle and syringe. Scopolamine is effective at blocking the muscarinic effects of acetylcholine in the central nervous system, and low doses of scopolamine can significantly reduce the amount of atropine needed for a patient. Opiates, phenothiazines, antihistamines, and succinylcholine should be avoided in patients that have been exposed to V-series nerve agents. [10][11][3][12][13][14]

• CBRNE - Chemical warfare agents

• CBRNE – Nerve agents, binary - GB2, VX2

• CBRNE – Nerve agents, G-series – Tabun, Sarin, Soman

• Organic phosphorus compound and carbamate toxicity

• Organophosphate toxicity

The U.S. has stockpiles of all 3 antidotes (Atropine, pralidoxime, and benzodiazepine) in the CHEMPACK program. There are pre-hospital CHEMPACKS and Hospital-based CHEMPACKs with slightly different amounts of antidotes in them. The must be kept in a climate control location and linked by secure phone connections to a central location that monitors whether they are opened.

The V series are lethal agents. Immediately decontamination and administering antidotes as soon as suspected will improve the chances of survival.

Consultation with the regional Poison Control Center is extremely helpful in these cases, especially on guidance for repeating doses and duration of treatment.

The assassination of Kim Jong-nam with VX in the Kuala Lumpur International Airport in February 2017 and the poisoning of Sergei and Yulia Skripal with a 'Novichok' (Russian for 'newcomer') nerve agent in the United Kingdom in March 2018 serve as examples of how nerve agent attacks with even one or two victims will quickly become international news. Once a patient has been diagnosed with a V-series nerve agent exposure, healthcare providers will be responsible for communicating not only numerous colleagues and staff but also with public health officials, law enforcement agencies, members of the media, and elected officials. The marshaling of resources to respond will almost certainly reach the national and international levels. (Level V)

Important communication points early in the care of the patient among physicians, nurses, and pharmacists will include adequate decontamination of the patient and appropriate precautions for first responders and hospital staff to avoid additional casualties. Training and education prior to such an event will be more effective than just-in-time training after an event has occurred when emotions run high and resources may run low. In large-scale events, it will be essential for healthcare staff to have a clear understanding of their available resources, and continuously communicating with government officials to access medical supply stockpiles and resources for the capacity to treat large numbers of patients will be vital. (Level V)