THE EFFECT OF MORPHINE AND PROSTIGMINE METHYLSULFATE

Abstract

Clinical reports have been presented which suggested that the combination of morphine and prostigmine methylsulfate has definite therapeutic advantages over morphine alone.¹ The investigations reported in the present paper were undertaken in the hope of obtaining more objective evidence regarding this reported potentiation. METHODS The Hardy-Wolff method of measuring pain thresholds was used throughout the study. The stimulus intensity at the threshold was measured either with a radiometer or with a wattmeter connected in the lamp circuit, it having been previously shown that there is a linear relationship between these variables over a wide range of intensities.² At each test several determinations were made until a satisfactory threshold was established. The desired dose was then administered subcutaneously and the pain threshold redetermined at intervals of fifteen minutes until it returned to its original value, or until it was evident that the drug given had not produced an effect.