DERIVATION.--Potassium iodide may be prepared in the same manner as
potassium bromide iodine, being used in place of bromine.
PROPERTIES.--It is a colorless, transparent, translucent, or opaque
white, cubical crystals, or white granular powder, having a peculiar,
faint, iodine-like odor and a pungent, saline, afterwards bitter, taste.
Permanent in dry air and but slightly deliquescent in moist air. Soluble
in 0.7 parts of water, and in about 12 parts of alcohol at 77° F., in
0.5 parts of boiling water, in 6 parts of boiling alcohol; also soluble
in 2.5 parts of glycerine.
ACTIONS.--Potassium iodide closely resembles iodine but is less
powerful and devoid of local irritant action. Medical doses are
antiseptic, desquamatic, deobstruent, expectorant, alterative and
diuretic. It stimulates the lymphatic system. It is readily soluble, and
is quickly absorbed in the tissues, where it undergoes decomposition;
the iodine, when liberated, apparently combines with albuminoids and
acts specially on the lymphatic glands and vessels, modifying nutrition,
hastening metabolism and promoting absorption. It is doubtless in this
way that it also unites with lead and mercury deposited in the tissues,
renders them soluble, carries them into the circulation and causes their
elimination.
It is quickly excreted by the mucus and skin surfaces, but chiefly by
the kidneys.
USES.--Potassium iodide is useful in promoting absorption of enlarged
lymphatic glands, and its action should be assisted by the application
of iodine or red iodide of mercury externally. Potassium iodide in small
doses diminishes congestion and increases the fluidity and amount of
secretions in acute laryngitis, acute and subacute bronchitis, and
appears to possess an alterative action in improving the condition and
nutrition of the bronchial mucous membranes. It is also of some value in
asthma, pulmonary emphysema and chronic bronchitis, unassociated with
copious secretion. Chronic pleuritis, pericarditis and ascites are
treated with potassium iodide, which assists absorption and occasionally
exerts a diuretic effect. Tardy resolution of pneumonia consolidation is
hastened by potassium iodide. Endocarditis with cardiac hypertrophy is
said to be benefited by potassium iodide and digitalis.
Champignon, or scirrhous cord in horses, is sometimes cured by the
sorbefacient powers of potassium iodide in full doses. Potassium iodide
is of value in goiter of dogs, calves and sheep when tincture of iodine
is used externally. “Roaring” and “thick wind” may be cured by the
administration of potassium iodide. It is the best medicine known for
actinomycosis. Potassium iodide has a clinical reputation for its power
to aid absorption and resolution in inflammation or effusions of the
brain or spinal cord, in paralysis of the body or limbs and inflammation
of the membranes covering the brain.
DOSES.--Horses, 2 to 4 dr.; cattle, 3 to 6 dr.; sheep and pigs, 15 to 30
gr.; dogs, 1 to 10 gr.
It should be given to the larger animals in doses of three drachms
daily, until iodism appears, which shows itself by loss of appetite, an
irritable, catarrhal condition of the mucous membranes of the nostrils,
eyes, throat and digestive organs, a vesicular skin eruption, abstinence
from water, diminished secretions of urine, temperature elevated and
emaciation.