The long-acting anticholinesterase drugs in the management of myasthenia gravis

Abstract

1. 1. The published studies on the treatment of myasthenia gravis with long-acting anticholinesterase drugs—di-isopropylfluorophosphate (DFP), hexaethyltetraphosphate (HETP), tetraethylpyrophosphate (TEPP), and octamethyl pyrophosphoramide (OMPA)—have been reviewed and correlated with studies on 21 patients treated by us with OMPA. 2. 2. The data indicate that OMPA possesses most of the desirable qualities which could be expected of long-acting anticholinesterase compound for the use in the management of myasthenia gravis: it is stable in aqueous solution; it is well absorbed when administered orally; it is highly effective in producing “irreversible” inhibition of ChE; finally, it is essentially free of actions on the central nervous system. The data also suggest that it is improbable that any other compound whose effects are due to more or less “irreversible” inhibition of ChE will prove significantly superior to OMPA in the management of patients with myasthenia gravis. 3. 3. Long-acting anti-ChE agents should not be administered to patients with myasthenia gravis of progressively increasing severity and should be given only with great caution to patients with stable but severe disease. 4. 4. Octamethyl pyrophosphoramide (OMPA) is an excellent agent for the treatment of the patient with only moderately severe and stable myasthenia gravis. By its use some patients can be transformed from semi-invalidism to essentially normal activity. 5. 5. Experience with the long-acting anticholinesterase drugs demonstrates that even maximal inhibition of peripheral ChE may fail to control myasthenic weakness. Adequate management of severe or progressive instances of the disease must await a better understanding of its pathologic physiology.