Iodine is a non-metallic element of bluish color, derived chiefly from the ashes of sea-weeds; not readily soluble in water; soluble in ether, alcohol, and glycerin. It is never given internally in crude form.

Physiological Actions

Applied externally iodine is an irritant and vesicant, and stains the skin yellow, or, in repeated applications, deep brown. It causes some pain, with a feeling of warmth, and desquamation may follow its use. It is absorbed into the blood partly through the skin and partly in the form of vapor.

The vapor of iodine, like that of chlorine, but in a feebler degree, decomposes sulphuretted and phosphu-retted compounds, and is, therefore, antiseptic and disinfectant. Internally iodine excites a sensation of heat and burning in the stomach. In sufficient quantity it is an irritant poison, causing inflammation of the lining of the stomach, severe pain in the abdomen, vomiting, and purging. The matters vomited have a yellow color, except when farinaceous food has been taken; in this case they are blue or purplish. The amount of iodine necessary to produce toxic symptoms varies with constitutional peculiarities and with the kind and amount of food in the stomach. Death has been caused in twenty-four hours by ʒ i. The antidote is starch or flour stirred up in water, and emetics should be given afterwards.

Iodine is rapidly excreted, appearing in the urine, the perspiration, saliva, bile, milk, and mucous secretions, especially of the air-passages.

Preparations Of Iodine

Potassii Iodidum. Potassium Iodide

Made by dissolving iodine in liquor potassae, evaporating, and treating the residue with wood charcoal.

Potassium iodide is extremely diffusible and enters the blood with great rapidity. It acts in a general way as a tonic and stimulant to nutrition, accelerates tissue-changes, and increases the excretion of waste products. It has some slight diuretic action, and has the power of dislodging from the tissues various poisonous metallic substances, notably lead and mercury.

The lymphatic glands are reduced in size by iodide of potash, and, like mercury, it has over some forms of disease a marked and positive influence, not thoroughly explainable. Its action in these cases is called "specific" or "alterative."

Incidental Effects

In giving any of the iodides, and especially the iodide of potash, the peculiar set of symptoms known as "iodism" must be carefully watched for. There is first an inflammation of the mucous membrane of the head resembling acute coryza, or catarrh; running at the eyes and nose, salivation, swelling of the eyelids, sneezing, and frontal headaches; sore-throat, hoarseness, and trouble in swallowing, with a feeling of general wretchedness, and rise in temperature.

There are also several varieties of eruptions which may appear, said to be more likely to occur in the case of patients with diseased kidneys. The most common is an eruption of acne on the face, shoulders, and thighs, and eczema is also frequent.

Debility and pains in the joints are sometimes noticed, and in some cases digestive disturbances result, with nausea and diarrhoea.

The solution of 1 in 1 (e i. = gr. i.) is best given in milk; or it may be given in cinnamon water, or the compound syrup of sarsaparilla, to disguise the unpleasant taste. It is often ordered with bichloride of mercury, and they may be given together, but if it is not ordered in combination it should never be added to any other medicine, but given alone.

By largely diluting it and giving it on an empty stomach, symptoms of iodism are in a measure avoided.

Potassium iodide is given pleasantly and with great freedom in aromatic spirits of ammonia.

Average dose, gr. v.-0.3 Gm.

Liquor Iodi Compositus. Compound Solution Of Iodine. Lugol's Solution

Composed of iodine and potassium iodide - of the former, 5%.

Average Dose, E III

0.2 mil, well diluted.

Tinctura Iodi. Tincture Of Iodine

Contains 70 Gm. iodine, and 50 Gm. potassium iodide, in 1000 mils alcohol.

Recent surgical work has given the iodine tincture a distinguished place in the technique of disinfection and treatment of wounds. It was formerly used simply as a counterirritant, painted on the skin as ordered, with a camel's-hair brush. If the application is painful and it is desirable to remove it, a weak solution of ammonia will take it off.

Unguentum Iodi. Iodine Ointment

Contains 4 parts in 100 of iodine, with 4 parts of potassium iodide, 12 parts glycerine, and benzoinated lard to make up the rest.