Because of frequent complaints of pain by patients receiving streptomycin injections on the tuberculosis wards of the Philadelphia General Hospital, an investigation was made to determine the cause. After eliminating obvious variables such as the method of injection and the size of the needle used by the nurses, it was discovered that two different salts of streptomycin were being used haphazardly, the sulfate and the calcium chloride complex, both supplied by the same pharmaceutical company. Since a previous report by Durrance1 stated that calcium chloride complex salt of streptomycin caused pain when injected intramuscularly, the following study was carried out.
Over a period of several weeks, biweekly injections were given to 65 patients. The calcium chloride complex was used in the first three injections, and the sulfate salt was substituted in the last three injections. Spontaneous complaints of pain at the time of injection or within the following 24