Therapeutic and neuroprotective efficacy of pharmacological pretreatment and antidotal treatment of acute tabun or soman poisoning with the emphasis on pretreatment drug PANPAL.

A good knowledge of the basic mechanisms of acute toxicity of organophosphorus compounds has lead to the development of specific antidotes able to counteract their acute toxic effects. Unfortunately, there are still some highly toxic organophosphorus compounds, called nerve agents, that are resistant to standard antidotal treatment. Relatively unsatisfactory antidotal treatment of acute poisonings with some nerve agents has prompted studies of pretreatment possibilities that would increase the resistance of organisms exposed to nerve agents. Current protection against nerve agent poisoning is pyridostigmine, but its prophylactic efficacy is rather limited. To increase the effectiveness of pharmacological pretreatment of soman or tabun poisoning, a prophylactic mixture called PANPAL and consisting of pyridostigmine and two anticholinergic drugs - benactyzine and trihexyphenidyle was developed, produced and introduced into the Czech Army to protect soldiers against nerve agent exposure. This review describes the evaluation of the potency of PANPAL to counteract acute soman or tabun poisoning and to increase the therapeutic and neuroprotective efficacy of current post-exposure antidotal treatment in comparison with pyridostigmine given alone as pretreatment.