Definition. - The inner anhydride or lactone of santonic acid, obtained from Santonica.

Description and Properties. - Colorless, shining, flattened, prismatic crystals, odorless, and nearly tasteless when first put into the mouth, but afterward developing a bitter taste; not altered by exposure to air, but turning yellow on exposure to light. Nearly insoluble in cold water; soluble in 34 parts of alcohol. Santonin should be kept in dark, amber-colored vials, and should not be exposed to light.

Dose. - 1/4-1 grain (0.016-0.06 Gm.) for a child; 1-5 grains (0.06-0.32 Gm.) for an adult [1 grain (0.065 Gm.), U. S. P.].

Official Preparation

Trochisci Santonini - Trochiscos (acc.) Santomini - Troches of Santonin. - Each troche contains 1/2 grain (0.03 Gm.). Dose. - 2 (child) to 10 (adult) troches.

Physiological Action and Therapeutics. - In full or large doses santonin may excite nausea or vomiting, with abdominal pain, diarrhea, eructations, borborygmi, and great thirst. It readily enters the blood, where it exists as sodium santoninate. Large doses may cause giddiness, headache, hallucinations of smell and taste, tremors, and a species of depression, the combination of symptoms forming what is called santonin intoxication.

The drug is chiefly eliminated through the kidneys, small amounts of santonin even imparting to the urine a distinct yellow color if the urine is acid, and a decided purplish or even red color if the urine is alkaline. Under certain circumstances when the urine is decidedly alkaline, as in cases of cystitis, the administration of santonin may produce so marked a discoloration of the urine as to suggest hematuria.

Probably the most remarkable phenomenon attending the ingestion of medicinal doses of santonin is that of xanthopsia or yellow vision, which may continue for several hours. According to Rose, "there occasionally appears before the peculiar yellow sight, after large doses of santonin, a violet color of the field of vision: the intensity of this color is in proportion to the darkness of the objects looked at. All light objects, such as windows, paper, etc., appear actually yellow. Red and blue appear often in their complementary colors, orange and green, so that carmine-red appears pale, madder-red a bronze color, and the sky and blue objects green. This, however, is not always the case, and it has been noticed after the employment of santonin that red appears violet or light, and dark objects appear orange to one person, and to another green." (Quoted from Lewin.) This peculiar effect of santonin is due, according to Rose, to a nervous change in the retina or in the brain.

Affections of the skin - e. g., urticaria - have occasionally followed the administration of santonin. Decidedly poisonous effects have sometimes been produced by comparatively small amounts of the drug. The symptoms of a fatal case from over-dose of santonin were convulsions accompanied by unconsciousness, twitching of the eyeballs, dilated pupils, cold sweat, weak pulse, feeble respiration, and, after some hours, sudden death.

In case of poisoning by santonin the remedial measures are internal and external stimulants, eliminants, and artificial respiration. Santonin is certainly a most efficient remedy against the ascaris, and to a less extent it is of use against the oxyuris. It has no effect on the tcenue.

The drug should be given on an empty stomach, preferably at night, either alone or associated with calomel, and followed in two or three hours by castor oil or other brisk cathartic. It may be administered in the form of a powder mixed with sugar or jelly, or in pills or capsules. Troches of santonin are much used and are very efficient. Care should be taken that they are fresh and that they should not be permitted to remain a great length of time in the intestine.