This section is from the book "Materia Medica And Therapeutics Inorganic Substances", by Charles D. F. Phillips. Also available from Amazon: Materia medica and therapeutics.
In those cases of thoracic and abdominal aneurism, in which surgical treatment is impossible or highly dangerous, the clinical results obtained by iodide of potassium should not be ignored. Nelaton recorded marked relief to the signs and symptoms of an innominate aneurism under the use of this remedy, which he gave empirically at the request of the patient; and Bouillaud, following up this clue, obtained good results in aneurisms of the carotid and thoracic vessels (Medical Times, i., 1859).
Chuckerbutty, in Calcutta, published three cases relieved, in one of which the aneurism was already projecting through the sternum when the drug was commenced, and Dr. W. Roberts and Mr. Windsor recorded some equally striking results about the same time (British Medical Journal, ii., 1862; i., 1863).
It is, however, to Dr. Balfour that we are most indebted for drawing professional attention to this subject (Edinburgh Medical Journal, 1868-1869). He summarizes 15 cases, all of which, save one, were relieved, and in 12 the external tumor was actually lessened and the sac partly consolidated. In one of his earliest patients the bulging, which was evident between the second and third ribs, disappeared after a few weeks' treatment with 30-gr. doses thrice daily, and this dose was continued for nine months "without any unpleasant symptoms," but with complete subsidence of aneurismal suffering. The same man had not improved under previous doses of 20 gr., and Dr. Balfour points out the importance of pressing the drug to saturation before considering it inert. It is very quickly eliminated - large doses within two or three days - and many of his patients took 20 to 30 gr. several times daily. In a few, coryza and headache were quickly induced, and 5 gr. only were tolerated, but, as a rule, no worse symptoms were caused by large than by small doses. Additional evidence in favor of this treatment has been furnished by Dr. W. Roberts, Dr. Shapter, and others (Medical Times, 1874; British Medical Journal, 1873-74), and recently Dr. Philipson has reported a cure of an abdominal aneurism (British Medical Journal, i., 1878).
It seems to me no argument against such cases to say, with Dr. Bristowe, that any remedy which coagulates the blood in an aneurismal sac must tend to coagulate it elsewhere, and is therefore inadmissible; or to note with Mr. Holmes that aneurism may sometimes develop in patients already under the influence of iodide (Medical Times, i., 1872). This is only saying that the remedy is not infallible, and that its mode of action, whether on the composition or vital condition of the blood (Chuckerbutty, Roberts), on the nervous system (Balfour), or on the walls of the sac, is not yet clear. I have myself seen remarkable advantage from its use, and suggest, in addition to the above explanations, a possible anti-syphilitic effect - for the occasional connection of syphilis and aneurism is sufficiently proved by modern research.