Related entry: Dioscorea.—Wild Yam
Preparation.—Make a saturated tincture of the powdered root of Dioscorea villosa, and filter; add the tincture to its weight of water, and carefully distill off the alcohol; the resinoid principle will be left behind in the water, collect, dry, and pulverize it. This is the original formula as named to me by Mr. Wm. S. Merrell, for its preparation, about the time of its introduction to the profession.
History and Description.—The profession is indebted to Mr. Wm. S. Merrell for the preparation and introduction of this agent; it having been first prepared by him in the winter of 1852-3. Dr. T. L. A. Greve states that the article which has been sold for some years past, and is still sold under the name of Dioscorein, is the alcoholic extract of the root, dried and powdered (King). This statement of Dr. Greve is in accordance with our views, and we believe that the term Dioscorein is improper. This preparation and a few others of similar composition are retained in the class of extracts which they occupied in preceding editions of this publication. (See remarks on resinoids and concentrations under Resina Podophylli).
Medical Uses and Dosage.—Extract of dioscorea possesses the properties of the crude root in an eminent degree, and is undoubtedly as much a specific in bilious colic, as quinine is in intermittents. In a severe case of bilious colic, pronounced past hope by several physicians, 4 grains rubbed up with a tablespoonful of brandy afforded prompt relief, and a repetition of the dose, in about 20 minutes from the time of taking the first, effected a cure. In ordinary cases, 1 or 2 grains of this extract may be administered every 5, 10, or 20 minutes, according to the urgency of the case. In flatulence, borborygmi, etc., it may be advantageously combined with ginger, extract of aletris, or of asclepias; in many forms of uterine disease its union with resin of black cohosh, oleoresin of senecio, resin of blue cohosh, etc., will prove very useful; and it may be combined with the extract of Cornus sericea, to overcome the nausea and vomiting of pregnant females. In cramp of the stomach, or painful spasmodic affections of the bowels, a pill or powder composed of equal parts of extract of dioscorea, resin of blue cohosh, and extract of high cranberry bark, will be found a remedy of great value, as well as in after-pains; the mixture should be given in 3 or 4-grain doses, and repeated every half hour or hour. It is strictly an American remedy, of great value. Dose, from 1 to 4 grains, repeated as circumstances require (J. King).
King's American Dispensatory, 1898, was written by Harvey Wickes Felter, M.D., and John Uri Lloyd, Phr. M., Ph. D.