190 .^ INORGANIC AGENTS 



PoTASsii loDiDUM. Potassium Iodide. K I. (U. S. & B. P.) 



Synonym. — Jodkalium, G. ; kalium iodatum, P. G.; iodure de potassium, Fr, 



Derivation. — Iodine is dissolved in hot liquor potassK. 6 1+6 K O H =5 

 K I+K I O3+3 H2O. The evaporated residue is heated with charcoal to remove 

 O from K I O3 (Potassium lodate). KIO3+3 C = KI+3 C O. The result is 

 purified by crystallization. 



Properties.-r-CMhicaX crystals, either transparent and colorless or more or less 

 opaque and white, or as a white, granular powder, having a pungent, saline, after- 

 wards bitter taste. Permanent in dry air, but slightly deliquescent in moist air. 

 It is soluble in 0.7 part of water; in 22 parts of alcohol, and 2 parts of glycerin. 



Dose.— H., 3ii-iv, (8-15); C, 3vi, (24); Sh. & Sw., gr.xv-xxx, (1-2); D., 

 gr.ii-x, (.12-.6). 



SoDii loDiDUM. Sodium Iodide. Na I. (U. S. & B. P.) 



Synonym. — Iodure de sodium, Fr.; jodnatrum, G.; natrium iodatum, P. G. 



Derivation. — Made from sodium hydrate in the same manner as potassium 

 iodide. 



Properties. — Colorless, cubical crystals, or as a white, crystalline powder, 

 odorless and having a saline taste. In moist air sodium iodide deliquesces, or at 

 first cakes and then deliquesces, and frequently undergoes decomposition, assum- 

 ing a brown tint. Soluble in 0.55 parts of water and in 2 parts of alcohol. 



Dose. — Same as potassium iodide. 



Syhupits AciDi Hydeiodici. Syrup of Hydriodic Acid. (U. S. P.) 



Contains 1.3 to 1.45 per cent, of H I. 



Derivation. — ^Diluted hydriodic acid, 125; water, 300; syrup, 575. 



Properties. — A transparent, colorless, or not more than pale, straw-colored, 

 syrupy liquid; odorless, and having a sweet and acidulous taste. 



Dose.— D., TTlxv-3i, (1-4). 



Action External. — Potassium iodide is not absorbed unless rubbed 

 into the skin with fat, and is not a local irritant^ and therefore possesses 

 very little value as an external application. 



Action Internal. — Potassium iodide and iodine are both described 

 by that unsatisfactory term^ alterative. In certain diseases, as in rheu- 

 matism, iodine and the iodides alter nutrition and cause absorption of 

 exudates in some unknown manner ; hence the term alterative. Potassium 

 iodide forms in the tissues soluble double salts with the metals and there- 

 fore is the antidote in chronic lead, arsenic, mercury and zinc poisoning 

 in aiding their elimination. It is often taught that potassium iodide 

 liberates iodine in the tissues, and that the latter forms soluble com- 

 pounds with albumin, which are then readily eliminated; thus explaining 

 the effect of potassium iodide in aiding resolution of morbid exudation 

 and inflammatory thickenings. Free iodine is certainly formed in the 

 body as it escapes into the stomach after administration of iodides. 

 Iodides produce untoward symptoms (iodism) in medicinal doses more 

 often than most other drugs. Those most characteristic resemble influ- 

 enza in there being pain over the frontal sinus, running of the eyes and 

 nose, sore throat, tenderness of the teeth and gums, and sometimes 

 glandular swelling about the throat and parotids. An acneform, or more 

 rarely, furuncular or purpuric eruption may occur. Often these unfor- 

 tunate symptoms appearing with small doses may disappear with large 

 ones. Arsenic and alkalies given with iodides lessen the likelihood of 

 iodism. The sodium iodide is less irritating than the other salts. Occa- 

 sionally there is fever. 



Iodides stimulate thyroid activity and are to a certain extent taken 



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