Selecting the Streptomycin Regimen for Patients with Pulmonary Tuberculosis with Special Reference to the Intermittent Dosage Schedule

¹ The Tuberculosis Division, Medical Service and Laboratory Service, Fitzsimons General Hospital, Denver, Colorado.

On the basis of current streptomycin research studies at Fitzsimons General Hospital, certain tentative conclusions regarding the type of streptomycin regimen to select in the treatment of patients with pulmonary tuberculosis seem justified, as follows:

1) We should use the shortest course of streptomycin therapy which will accomplish our purpose, in order that we may reduce the number of cases developing "bacterial resistance."

2) That short courses ( 30-60 days) of streptomycin are satisfactory for most cases of pulmonary tuberculosis with recent exudative lesions.

3) That long courses ( 60-120 days) of streptomycin are better and often required in the treatment of patients with caseous pneumonic tuberculosis ( particularly severe acute lobar or lobular pneumonia). In these cases where streptomycin may prove to be life saving, the danger of " bacterial resistance" must be disregarded.

4) That long courses of treatment or interrupted short courses of streptomycin over a long period of time are required for miliary pulmonary tuberculosis with or without meningitis.

5) That the intermittent streptomycin schedule¹ using one or two grams of the drug every third day for one to four months, will give clinical and roentgenological results comparable to those obtained by one or two grams daily dosage schedules over similar periods of time, without significant toxic reactions to the drug. In addition, the important factor of delaying the emergence of streptomycin resistant organisms is proved. In our series, no case with "bacterial resistance" developed in 42 days; only 3.9 per cent at 60 days; 4.2 per cent at 70 days; 8 per cent at 80 days; 18 per cent at 90 days; 24 per cent at 100 days; and 33 per cent at 120 days. In other words, this effective method of using the drug can be utilized for a prolonged period with less danger of encountering "bacterial resistance" than from any of the other regimens reported upon in this study. The intermittent regimen can be used for periods of from one to four months or longer, either continuously or in interrupted short courses, depending upon the purpose for which it is prescribed. Of all courses of streptomycin therapy studied at Fitzsimons General Hospital, it appears to have the greatest utility in the management of all forms of pulmonary tuberculosis ( exclusive of miliary tuberculosis) , whether its purpose be for definitive treatment, as an adjunct to operative procedures, for symptomatic relief, or as a therapeutic trial. ( Research studies are now being made with the intermittent streptomycin schedules combined with 12 grams of para-aminosalicylic acid ( PAS) orally daily, in the hope of still further delaying the emergence of drug resistant organisms).