Ototoxicity from intermittent streptoduocin therapy of pulmonary tuberculosis; a study of one hundred five patients treated eight to ten months.

In 1954 Cline, Houseworth and Pitts reported on an ototoxicity study of 100 patients treated in this institution with intermittent streptomycin. I t was felt that this study should be compared with a similar series treated with streptoduocin, a mixture of equal parts of streptomycin and dihydrostreptomycin, to see if there was any significant difference in a degree or type of ototoxicity. Materials and Methods A group of 105 hospitalized pulmonary tuberculosis patients were treated for a minimum of eight months and a maximum of 10 months. These patients were mainly young adult men; all received two grams of streptoduocin intramuscularly every third day for six months after which the dose was reduced to one gram every third day. In addition, all of them received isoniazid and/or para-aminosalicylic acid orally. None in this series had more than 30 days of streptomycin or dihydrostreptomycin or other ototoxic drugs within 12 months prior to the study. Audiometer testing was done with a model H-l maico audiometer, and vestibular function was tested grossly by means of an ice water test, as described in the earlier report.' Arbitrary criteria for evaluating the degree of dysfunction have been defined as follows: 1. None-less than 10 db loss of hearing and/or nystagmus of 90 or more seconds. 2. Sl igh t loss of 10-20 db and/or nystagmus of 75 to 89 seconds. 3. Moderate-loss of 21-30 db and/or nystagmus of 50 to 74 seconds. 4. Severe-loss of more than 30 or more db and/or nystagmus of less than 50 seconds, including no reaction. For purposes of evaluation the audiograms have been divided into two groups--the low or conversational frequencies represented by the 512 through 2048 cps range and the high tones represented by the frequencies of 4096 to 8192 cps. Results As noted in Table I, 43 (40.9 per cent) of the total series showed either some degree of dysfunction at the end of eight to 10 months of therapy or an increase in their original dysfunction. Eighty-five per cent of these abnormal results revealed only slight dysfunction and 7.5 per cent abnormal From the Pulmonary Disease Service, Fitzsimons A m y Hospital, Denver, Colorado. *The Streptoduoein was furnished by the Chas. Ptizer Co., Inc. in the fonn of Combi-strep.