USE OF OCTAMETHYL PYROPHOSPHORAMIDE IN THE TREATMENT OF MYASTHENIA GRAVIS

Abstract

Octamethyl pyrophosphoramide (OMPA) is the most recent organic phosphorus anticholinesterase agent used in the treatment of myasthenia gravis. The pharmacology of this drug has been extensively studied by DuBois, Doull, and Coon.¹ It is not itself an active antisterase agent, but it is converted to an active substance by the liver. Like the other organic phosphorus compounds, such as di-isopropyl fluorophosphate and tetraethyl pyrophosphate, and in contrast to neostigmine, the active metabolite of octamethyl pyrophosphoramide inhibits cholinesterase irreversibly. It is for this reason that all of these compounds have the advantage over neostigmine of a longer duration of action. The advantages of OMPA over the others lie in its greater chemical stability and less severe toxic side-effects. Muscarinic symptoms from octamethyl pyrophosphoramide are more easily controlled with atropine than are those produced by diisopropyl fluorophosphate and tetraethyl pyrophosphate, and, furthermore, OMPA, because of its exclusively peripheral action, does not