Iodoformum

Iodoform

Iodide of formyl. Small, lemon-yellow, lustrous crystals of the hexagonal system, having a saffron-like and almost insuppressible odor, and an unpleasant, slightly sweetish iodinelike taste. Not perceptibly soluble in water, to which it imparts a slight odor and taste; soluble in 80 parts of alcohol at 15° C. (59° Fahr.) and in 12 parts of boiling alcohol, in 5·2 parts of ether, and in chloroform, benzol, benzin, disulphide of carbon, fixed or volatile oils. It sublimes slightly at ordinary temperatures. (U. S. P.)

Unguentum Iodoformi

Iodoform ointment. Iodoform, 10 grm.; benzoinated lard, 90 grm.

Actions and Uses

Notwithstanding iodoform contains 97 per cent of iodine, it possesses properties in some respects different from that agent. Discovered by Sérullas in 1822, it was not prescribed until 1836, when Bouchardat used it because of the large quantity of iodine contained in it. In 1853 D'Olleggio brought it forward as a disinfectant and deodorizer; and in 1856 MM. Moretin et Humbert showed it might be substituted for the iodides, because easily absorbed and free from any irritant properties. They also demonstrated that iodoform has anodyne effects, that it induces analgesia of the rectum when applied to it, and that it can be used in the same classes of disease as iodine, and in some neuralgias and painful affections of the bladder and prostate. In 1866 Dr. Eastlake, in the course of a paper on uterine therapeutics, referred to iodoform as a valuable sedative in uterine cases. Dr. Greenhalgh soon after confirmed these observations. The following year, Voelker added some new facts of the same kind. In 1868 Féréol, in a paper read before the Therapeutical Society, gave full details regarding the effects of iodoform on wounds, fully anticipating many of the observations since made on its antiseptic and healing properties.

Little attention had been given to iodoform in Germany, before the investigation made bv Binz. Moleschott followed these researches bv some important chemical observations, and afterward Mosetig and Mikulicz, of Vienna, and Gussenbauer, of Prague, set forth the remarkable virtues of this substance as an antiseptic dressing. Since these communications appeared, the use of iodoform has received enormous extension, and its popularity has attained to such extravagant proportions, that the wide-spread enthusiasm may be entitled iodqform-mania. There can be no question, however, as to its utility. There are, nevertheless, limitations to its employment, imposed by the nature of the substance. It seems desirable, hence, to set forth in a special article its actions and uses, according to the modern conceptions of its powers.

As iodoform contains 97 per cent of iodine, it may be supposed to have analogous properties, but, as the iodine is combined with the radical formyl, another influence enters into the action. Applied in the form of crystals or as a powder, the immediate effect is that of the compound—iodide of formyl—and not that of iodine merely, or of formyl merely; but the latter distinctly modifies the former; hence there is more or less of an anodyne effect. Binz holds that when iodoform is applied to a wound it is dissolved in the fatty bodies of the organism, and that iodine is disengaged to form iodides and iodates. Hogyes, on the contrary, maintains that the iodine when set free unites with albumen, and afterward forms salts. Moleschott explains the more energetic action of iodoform by the assumption that it is readily decomposed in the blood, and that the free iodine in its nascent form has more energetic affinities (Rohmer). In what manner soever its mode of action may be explained, the main point, in regard to which all are agreed, is, that the action of iodoform is chiefly due to the iodine. The effects of iodine have already been set forth, and hence no further statements are necessary; but the antiseptic action of iodoform, to which its present applications are chiefly due, requires further exposition. Mikulicz has especially studied the effect of iodoform on decomposing animal substances, and he finds that it prevents change and arrests decomposition when begun. For the purpose of determining its power to prevent putrefaction, he employed Pasteur's liquid, composed of extracts of foods, of malt, of peptones, of alkaline urine, and of bouillon, and blood, and covered this mixed solution with powder and crystals of iodoform. The experiment was varied by adding iodoform in different quantity to solutions having the same composition, and a "control experiment" was employed, to verify the results. It was shown that, in those solutions treated with sufficient iodoform, there was absolutely no development of minute organisms, while in the "control" fluid the germs were abundant and the putrefactive process active. In contact with wounds it has a very prompt and thorough antiseptic action. It promotes union and cicatrization, and at no time are there any heat, redness, swelling, or pain produced by it at the point of application. There is very little secretion from the wound treated by the application of iodoform, and the little observed has rather a serous than a purulent character. When a considerable loss of substance is to be closed by granulations, iodoform does not act so well, it is said, and hence, when the granulations have filled the wound up to the level of the skin, it is better to substitute solutions of nitrate of silver, of acetate of lead, etc.

Notwithstanding iodoform acts in many respects like iodine, there are differences. When the iodides or iodine tincture are given in sufficient doses, among the phenomena of iodism caused are coryza, pharyngeal and laryngeal catarrh, etc., and there ensues very considerable wasting of the tissues in general. On the other hand, when iodoform is given, wasting does not occur, but the body-weight increases, the complexion grows better, and the general condition improves in every way (Rohmer). It can not be affirmed, the author believes, that these beneficial results are constant for all doses of the remedy administered by the stomach, or for all quantity when applied topically. In fact, the first enthusiasm awakened by the discovery of the antiseptic powers of iodoform has been chilled by the untoward results of too lavish application. Not only dusted over the wounded surface, but applied in thick layers, it was soon found that, notwithstanding the slow absorption of iodoform, sufficient entered the blood to produce alarming, serious, even fatal symptoms.