Novichok agents: a historical, current, and toxicological perspective

Abstract

The Novichok, or "newcomer" class of nerve agents are lesser characterized, weaponized organophosphate agents. The use of known Novichok agents in warfare is banned under the Chemical Weapons Convention of 1997. Novichok agents are considered more potent than VX gas and can be applied in unitary and binary forms. Like other nerve agents, Novichok agents irreversibly bind acetylcholinesterase and produce a cholinergic toxidrome. Uniquely, these agents are thought to also target neurons in the peripheral nervous system. Delayed treatment or massive exposure may therefore cause a debilitating neuropathy. The recent 2018 assassination attempt of Russian dissident Sergei Skripal and his daughter Yulia in the United Kingdom highlights the importance of recognizing the potential lethal effects of these nerve agents. Treatment of Novichok agent poisoning is similar to management of other nerve agents. Given increasing worldwide incidents attributed to chemical weapons such as Novichok agents, clinicians should know how to rapidly recognize symptoms of acute poisoning and administer life-saving antidotal therapy, when indicated.

Keywords: Novichok; chemical weapons; nerve agents; organophosphates.

Figure 1

(a) Organophosphate structural backbone of Novichok agents. R =alkyl, alkoxy, aklylamino, or fluorine; X =halogen (F, Cl, Br) or pseudohalogen (CN). (b) Chemical structure of A-234 as described by Mirzayanov, and (c) by Hoenig and Ellison [18,27].