Caffeine, Calcium, and Eaton-Lambert Syndrome

Abstract

Investigations were performed in four patients with a myasthenic syndrome in which fractional release of the immediately releasable acetylcholine at nerve terminals is defective (3 of them were typical of Eaton-Lambert syndrome), 35 patients with classical myasthenia and 20 normal subjects. In the four patients with myasthenicsyndrome, administration of caffeine produced an increase in amplitude of muscle action potentials evoked with single and repetitive nerve stimulation, and also provided a reduction of abnormally marked facilitation of muscle action potentials evoked shortly after single nerve stimuus and brief tetanic nerve stimuli. These effects of caffeine on neuroyal transmission were similar to those obtained after administration of calcium. Caffeine thus was found to have the same therapeutic effect as calcium on a myasthenic syndrome with fractional acetylcholine release defect. Both drugs provided no significant change in the conditions of classical myasthenics and normals.