Iodine, Iodides.

Iodum, Iodine,—is a non metallic element, existing in sea-water and sea-plants chiefly, and occurs in bluish-black plates, of rhombic shape, metallic lustre, peculiar odor, acrid taste and neutral reaction. It is sparingly soluble in water (1 in 5000), readily so in ether and in alcohol (1 in 10), also in a solution of potassium iodide or sodium chloride. Dose, gr. ss-j, but it is never administered in crude form.

Preparations.

Tincture Iodi—Tincture of Iodine,—7 per cent. Dose, ♏︎j-v, diluted.

Liquor Iodi-Compositus, Compound Solution of Iodine, Lugol's Solution,—has Iodine 5, Potassium Iodide 10, Water 85. Dose, ♏︎j-x, diluted.

Unguentum Iodi, Iodine Ointment,—I 4, Pot. Iod. 1, Aq. 2, Adeps, 93.

Ammonii Iodidum, Ammonium Iodide,—Dose, gr. v-xx.

Potassii Iodidum,—Dose, gr. v-ʒj. Unguentum Potassii Iodidi, 12 per cent.

Syrupus Acidi Hydriodici, Syrup of Hydriodic Acid,—1 per cent., ʒj-ʒiv.

Iodoformum,—Iodoform, Formyl Iodide,—lemon-yellow crystals, of vile and persistent odor. Dose, gr. j-v. To remove the odor, mix it with Thymol, gtt. ij ad ℥, or Balsam Peru, or Oil of Mirbane (Nitro-Benzol), gtt. xx ad ʒ, or Oil of Bitter Almonds, or Oil (Attar) of Rose.

Unguentum Iodoformi, Iodoform Ointment,—strength 10 p. c.

*Suppositoria Iodoformi (B. P.),—each suppository contains 3 grains.

*Iodol,—a grayish-yellow powder, insoluble in water, tasteless and odorless, and contains 85 to 90 cent. of Iodine in combination with Pyrol, a constituent of mineral oil. Dose, gr. ss-v, in tablet.

*Iodo-tannin,—is Tannic Acid in Tincture of Iodine. For local use.

*Iodized Phenol, Carbolated Iodine,—a mixture of Iodine and Carbolic Acid in various proportions, for local use in gynecology.

*Bismuthi Subiodidum, Bismuth Subiodide ,—a heavy, dark-red, impalpable powder, only used locally, as a dressing for wounds, sores, etc., and a substitute for Iodoform. [See ante, under Bismuth.]

*Aristol, Dithymol Iodide,—a combination of Iodine and Thymol, containing about 46 p. c. of the former; an amorphous, unstable, non-toxic powder, used locally as a substitute for Iodoform.

*Europhen, Isobutyl-orthocresol Iodide—contains about 27 p. c. of Iodine, which it gives up in the presence of water; an amorphous, yellow powder, perhaps the best of the substitutes for Iodoform.

Iodides of Arsenic, Silver, Mercury, Iron, Lead, Sulphur and Zinc, are classed with their other bases, being allied more closely with them, in their actions and uses, than with Iodine.

Physiological Action. Iodine is irritant, also vesicant if used in quantity, staining the skin yellow. Combining with the hydrogen of phosphuretted and sulphuretted gases it is a disinfectant and deodorant. The Iodides are very diffusible and rapidly excreted; setting free ozone and iodine at the points of elimination, they are irritant, inducing violent coryza, with soreness of the throat and eyes, headache and profuse mucous discharge, with irritation of the kidneys. They induce great waste and rapid elimination of waste products, causing anemia, emaciation, and depression, if used for any length of time. They combine with foreign substances in the system and remove them. Iodism comprises the foregoing symptoms, together with frontal headache, a saline taste in the mouth, dysphagia, an acne-form eruption on the face and limbs, and temporary impotence. Sometimes the eruption is furuncular, or even purpuric. Copious dilution of these salts with water promotes their excretion, and to a great extent prevents these results from following upon their continued administration, as is sometimes necessary in the treatment of disease.

Iodoform contains from 94 to 97 p. c. of Iodine. It is a local anaesthetic, and (clinically) an efficient antiseptic, inhibiting, if not destroying, the microbes of putrefaction and pus formation. If applied too freely to an extensive raw surface it may be absorbed in dangerous quantity, and produce symptoms of narcotic poisoning, with increased temperature, quick and feeble pulse, collapse and death. In small doses internally it is considered tonic and alterative, and to possess sufficient power against certain pathogenetic microbes to cause their disappearance from the morbid products accompanying the disease.

Iodol has the same action as Iodoform, but is odorless and is said to be devoid of toxic power. Though insoluble in water it dissolves readily in the gastric juices, and is rapidly absorbed and diffused through the system.

Toxicology. The antidote to free Iodine is Starch, with the object of forming an Iodized Starch, which should then be evacuated from the stomach. In chronic poisoning by the Iodides, a free salivary flow, excited by chewing Pyrethrum root, will hasten the elimination of the drug.

Therapeutics of Iodine. The Tincture is much used locally as a counterirritant, and an alterative application. Iodo-tannin is chiefly employed as an antiseptic and alterative application in local diseases. The preparations of Iodine are used with benefit in—

Catarrh and Hay Fever,—inhalations of Iodine or the Carbolate.

Inflammations,—Tincture of Iodine locally, to promote absorption.

Skin Diseases,—the Glycerite or Tincture, in chloasma, lentigo, lupus.

Chronic Diseases of the Spleen and Liver,— the Tincture or Ointment may be used locally for counter-irritation.

Glandular Tumors, hypertrophied tonsils, cervical cysts, etc.,—the Tincture or Compound Solution parenchymatously injected, is an efficient resolvent.

Empyema, Hydrocele, Ovarian Cysts, etc. ,—the Tincture injected undiluted, is one of the best applications to prevent return of the effusion.

Sores, Ulcers, Fissures, etc,—Iodoform, Iodo-tannin, or Iodized Starch, are highly recommended, as local antiseptics and alteratives.

Vomiting of Pregnancy,—drop doses of the tincture every hour, have often succeeded in very obstinate cases.

Therapeutics of the Iodides. They are especially used in—

Acute Catarrh and Hay Fever,—Potassium Iodide with Arsenic internally; also Iodine and Carbolic Acid in weak solution locally .

Chronic and Capillary Bronchitis,—the Ammonium Iodide, in small doses, rapidly administered, is remarkably efficacious.

Catarrhal Pneumonia,—the Ammonium Iodide, to prevent caseation of the products. Arsenic may well be combined with it.

Spasmodic Asthma,—Potassium Iodide, in 15 to 30-gr. doses, is often very efficient, especially when the asthma is due to bronchial catarrh.

Hepatic Cirrhosis, in the first stage,—Ammonium Iodide with Arsenic.

Duodenal Catarrh, and jaundice therefrom,—Ammonium Iodide.

Aneurisms,—Potassium Iodide, in large doses (gr. xv-xxx) is often curative of internal aneurisms, when conjoined with absolute rest.

Tertiary Syphilis, and many of its results, as neuralgiae, paralysis from gummata, syphilitic ulcerations, syphiloma of the internal viscera, chronic rheumatism and sciatica of syphilitic origin, lupus of syphilitic or scrofulous origin,—are all best treated by Potassium Iodide.

Mercurial Poisoning, and other chronic metallic toxaemiae, —Potassium Iodide, to promote elimination of the poison.

Malaria,—the Ammonium Iodide with Arsenic, in chronic malaria.

Tonsillitis, and simple sore throat,—a weak solution of Potassium Iodide.

Chronic Bright's Disease,—the prolonged use of Potassium Iodide has seemed to retard the progress of the parenchymatous changes.

Therapeutics of Iodoform. As a local application this agent and its substitutes have been extensively used in the treatment of epithelioma, chancre and chancroid, wounds, ulcers, sores, etc., and but for its offensive odor and the danger of its toxic action Iodoform would have been in unrestricted employment for all such conditions. Aristol and Europhen, if equally efficient, as is claimed, will doubtless replace it largely as a topical agent. Iodoform and Iodol are highly esteemed as internal remedies in—

Chronic Gastric Catarrh, and intestinal catarrh, ulceration of the gastrointestinal mucous membrane, etc., —Iodol given midway between meals.

Bronchitis, Bronchial Catarrh, and various respiratory neuroses,—Iodol has been found highly useful in many instances.

Tuberculosis,—has been successfully treated by Iodoform, which certainly does check the activity of the bacillus of that disease.

Diabetes,—has been apparently cured by Iodoform given internally.

Syphilis,—may be combated successfully by Iodoform or Iodol, in lieu of Potassium Iodide, in cases where the latter is indicated.

Hydriodic Acid is used as a substitute for Iodine and the Iodides, being less offensive to the taste and stomach. It is official only as the Syrup, the Acid itself not being a stable preparation.

A Compend of Materia Medica, Therapeutics, and Prescription Writing, 1902, by Sam'l O. L. Potter, M.D., M.R.C.P.L.