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 .