The leaves of the second year's growth of Hyoscyamus niger, a coarse plant native in Great Britain and naturalized in the United States. The active principles are two in number - hyoscyamine, a crystalline, and hyoscine, an amorphous, alkaloid. These principles have the same chemical formula as atropine, yet are not identical with it.

Physiological Actions

Hyoscyamus is a mydriatic, and has very much the same physiological actions as belladonna and stramonium. It has greater calmative and hypnotic powers than either of the others, due, it is stated, to its hyoscine, which is supposed to be much stronger than hyoscyamine, and to have marked qualities as a cerebral sedative.

Like the former two drugs, it is a cardiac and respiratory stimulant, the pulse under its influence being more regular than the pulse of daturine. It has the same stimulant action on the muscular fibres of the intestines, thus being somewhat laxative. In poisoning, the dry mouth, flushed face, dilated pupils, and busy delirium are the same as with belladonna and stramonium, and the treatment is the same. Hyoscyamine is rapidly excreted by the urine.

Preparations Of Hyoscyamus

Tinctura Hyoscyami. Tincture Of Hyoscyamus

Made in a strength of 10%. Average dose,  xxx -2 mils.

Fluidextractum Hyoscyami. Fluidextract Of Hyoscyamus

Average dose,  iii.-0.2 mil.

Hyoscyaminae Hydrobromidum. Hyoscyamine Hydrobromide

Average dose, gr. 1/200-0.0003 Gm.

Scopolaminae Hydrobromidum. Scopolamine, Or Hyoscine Hydrobromide

Hyoscine is a powerful hypnotic, and differs from atropine in reducing the pulse rate. This is the first evidence of its action, and is shown in a few moments. The fall may be from 8 to 20 beats in a moment, and this effect is the last to disappear. Hyoscine does not always dilate the pupils. It is eliminated by the urine.

Average dose, gr. 1/200-0.0003 Gm.