Iodoform is made by heating iodine with potassium carbonate, alcohol, and water, and allowing the crystalline deposit to settle. It consists of small, bright-yellow, lustrous crystalline scales, with a very strong and clinging odor, and sweetish taste. It contains about 97 per cent of iodine, and is freely soluble in oils, ether, and chloroform. It is slightly volatile at ordinary temperatures, and at a temperature above 239° F. emits vapors of iodine.
Iodoform was discovered in 1822, but was not used for some years. Before the perfecting of surgical technique it had great vogue for a time as a disinfectant and antiseptic. Iodoform gauze was much used for wounds and dressings, and the powder freely applied. This overuse caused many cases of poisoning, as it is absorbed with great facility through an abraded surface.
Such incidents checked its popularity, and its strong odor made patients averse to it.
As sterilization developed and other substances were evolved, the use of iodoform was diminished. In cases of poisoning by absorption through a wounded surface, the following symptoms may occur:
Rise of temperature as high as 104° F., or higher. This may be the only symptom; or with it there may be headache, a rapid and compressible pulse, and loss of appetite, the symptoms going off as soon as the iodoform is discontinued. Iodine is found in the urine in iodoform poisoning. More serious effects are: a grave depression of the system, and anxious melancholia; a restless mental condition, with very weak and rapid pulse, perhaps reaching 180; drowsiness, delirium, and collapse. Death sometimes occurs quickly, even though the application be stopped. The amount capable of causing fatal poisoning has been recorded as varying from 500 grains upwards. In using iodoform the extent of exposed surface through which absorption may take place is of more importance than the actual amount applied, which may not all be absorbed.
Iodoform is sometimes given internally, in pill or capsule. Average dose, gr. ii.-0.125 Gm.
Iodoform 10 parts, and benzoinated lard 90 parts.
Iodol is an unofficial substance which has been produced in the attempt to make an equivalent for iodoform, which should have its qualities without the unpleasant odor. It is obtained by the action of iodine on certain constituents of mineral oil, and contains about 85 per cent iodine. It is a yellowish-brown powder, which darkens on exposure to light. It is odorless, soluble in alcohol, ether, and chloroform; insoluble in water. It is said to be as efficiently antiseptic and disinfectant as iodoform, having the same deodorant and anaesthetic properties, but it is not much used.
Other derivatives of iodoform, unofficial, are:
Antiseptin. Losophane. Sozoiodol.