Santonin

Santonin, a drug used in the U.S.P. and B.P., consisting of colourless flat prisms, turning slightly yellow from the action of light and soluble in alcohol, chloroform and boiling water. It is derived from santonica which is the unexpanded flower-heads of Artemisia maritima. The dose is 2 to 5 grs. The only B.P. preparation is the trochiscus santonini, but the preparation sodii santoninas is official in the U.S.P. Santonin is an anthelmintic used to poison the round worm Ascaris lumbricoides.  It has no influence on tape-worms. It must be administered fasting and be followed by a purgative in order to expel the worm. The most convenient mode of administration is in capsules. For thread worms which infest the anus of young children, a suppository containing 2 to 3 grs. of santonin and used on alternate nights for three nights is effective. The U.S. preparation sodii santoninas is useless as a vermifuge and is used in diseased conditions of the optic nerve. Even small doses of santonin cause disturbances of vision, usually yellow vision or perhaps green (xanthopsia or chromatopsia). The urine also turns yellow and finally purple or red. These effects usually pass off in a few days. Large doses, however, produce toxic effects, aphasia, muscular tremors and epileptiform convulsions, and the disturbances of vision may go on to total blindness.