Controlled study of iodotherapy for childhood asthma

Abstract

Two doses of potassium iodide (KI) and an idcntical placebo tablet were given three times daily by mouth to 52 children with intractable asthma, ranging from 8 to 16 years of age. Each patient received in random order 12 week courses of KI, 900 and 300 mg. daily, and placebo given in coded form, according to a double-blind design. During each treatment period several indicators of the severity of asthma were recorded weekly and scored by methods described. Serum iodide levels and several aspects of thyroid function were assayed regularly. Evidences of side effects, including thyroid enlargement and acne, were also monitored. Examination of the results of individual responses, and the use of “improvement” and “condition” scores indicated that in the population as a whole asthmatic symptoms were improved by KI, particularly at the high dose level. There was, however, considerable variability in the responses observed in individual children. It is estimated that asthma improved significantly in 18 per cent, and moderately in another 46 per cent. The remaining 36 per cent did not seem to be influenced by KI with respect to symptoms of asthma. Moderate or marked thyroid enlargement occurred in 4 per cent of the children during treatment with KI, and barely palpable goiters in another 14 per cent, within three to six weeks after therapy was initiated. The enlargements were not clearly related to dose level, but no goiters occurred during placebo therapy. Acneform skin lesions were produced or aggravated primarily among the adolescents. While the mechanisms of action of KI in asthma remain unclear, the evidence presented here indicates that 300 mg. three times a day is a tolerable and effective dose for many children in the age ranges and population described. The efficacy is great enough to warrant further studies of the optimal uses of this drug.