The leaves and flowering tops of Hyoscyamus niger Linné (Nat. Ord. Solanaceae), collected from the plants of the second year's growth. Jusquiame, Fr.; Bilsenkraut, Ger.

Extractum Hyoscyami Alcoholicum

Alcoholic extract of hyoscyamus. Dose, gr. 1/6—gr. j.

Extractum Hyoscyami Fluidum

Fluid extract of hyoscyamus. Dose,τη v— 3 ss.

Tinctura Hyoscyami

Tincture of hyoscyamus. Dose, 3 ss — oz ss-

Composition

Hyoscyamus contains two active principles—hyoscyamine and hyoscine.

Hyoscyaminae Hydrobromas

Hyoscyamine hydrobromate. A yellowish-white, amorphous, resin-like mass, or prismatic crystals. Very soluble in water (0·3 part) and in alcohol (2 parts). Dose, gr. 1/60—gr. 1/4.

Hyoscycaminae Sulphas

Hyoscyamine sulphate. In white, indistinct crystals, or a white powder, without odor and having a bitter, acrid taste. Freely soluble in water (0·5 part) and in alcohol (2·5 part). Dose, gr. -1/60—gr. 1/4

Hyoscinae Hydrobromas

Hyoscine hydrobromate. In colorless, transparent, rhombic crystals, odorless and having an acrid, slightly bitter taste. Soluble at 59° Fahr. in 1·9 parts of water and in 13 parts of alcohol. Dose, gr. 1/80—gr. 1/10.

Antagonists, Incompatibles, and Synergists are the same as for belladonna. The observation of Ladenburg, that hyoscyamine and duboisine are identical, is important, and, if confirmed, will facilitate the introduction of the latter into practice. As hyoscyamine is difficult to procure and very expensive, and as duboisine, on the other hand, will probably be very readily procured in any quantity, the latter may be substituted for the former. Clinical facts of this kind must be acted on with caution. Identity of chemical constitution does not always mean identity in physiological action and in therapeutical power. Differences in molecular arrangement, not appreciable by chemical analysis, may influence, to a great extent, the mode of action. The clinical facts do not, thus far, warrant the adoption of the view that hyoscyamine and duboisine are mutually convertible.

Physiological Actions

As atropine, daturine, and hyoscyamine are similar if not identical in chemical composition and in physiological action, the remarks already made in regard to the actions and uses of belladonna are applicable to stramonium and hyoscyamus.

To these alkaloids must be added duboisine, which by Ladenburg is held to be identical with hyoscyamine. Studied from the physiological standpoint, daturine and hyoscyamine are regarded as identical in their effects by Oulmont and Laurent. As daturine is not employed, owing to its scarcity, and as hyoscyamine has been the subject of considerable study and clinical observation, we refer, in the following remarks, wholly to this alkaloid.

Hyoscyamine, as it occurs in commerce, prepared chiefly by Merck, of Darmstadt, is in two forms, a yellowish-white crystalline solid, which is represented as chemically pure, and a dark, resinous mass, having a strong, mouse-like odor, which is rather a concentrated extract, but appears to be little if at all inferior to the pure alkaloid, and consists, as is now known, for the most part, of hyoscine, and is necessarily as active as any salts of the alkaloid. It may be administered hypodermatically in this form. As now the salts of hyoscyamine are used, and are freely soluble, water is the only menstruum employed to make solutions. The hydriodate is, however, the best form for administration, as it is freely soluble in water. The great variations in the dose of the alkaloid are due to the fact that much of the supposed residual extract is merely the uncrystallized hyoscine. The dose, by subcutaneous injection, ranges from one sixtieth of a grain to one fourth, and by the stomach from one sixtieth to one grain.

Hyoscyamine causes the same dryness of the mouth, dilatation of the pupils, flushing of the face, rapid action of the heart and of the lungs, the busy delirium with hallucinations and illusions, which are caused by atropine, but its effects in these directions are less in degree. In the various observations which have now been made on man, with the considerable doses which have been found necessary in some cases, it has been definitely ascertained that hyoscyamine has somewhat less than atropine of the deliriant action and much more hypnotic effects. As regards the mechanism of its action on the pupil, on accommodation, on the heart and respiration, there is no actual difference between the two alkaloids.

The elaborate investigations of MM. Oulmont and Laurent have conducted them to the following conclusions: Hyoscyamine and daturine act especially on the sympathetic system, in small or moderate doses stimulating the vaso-motor fibers and raising the arterial tension, and in large doses paralyzing the vessels and lowering the arterial tonus. These effects are produced after section of the vagi. The alkaloids differ in their action on the heart—hyoscyamine rendering the cardiac movements more regular, and daturine causing intermittence. By direct contact, both alkaloids slow and finally stop the heart's action. Both accelerate the respiratory movements. In moderate quantity both increase the intestinal movements; in large doses arrest them. As regards the nervous system of animal life, they are both without action on the motor functions, but in toxic doses they blunt the cutaneous sensibility. They do not affect the contractility of muscular fiber. Their action in dilating the pupil is due to stimulation of the sympathetic, and not to paralysis of the third nerve. The various phenomena arising from the administration of these alkaloids are referred by Oulmont and Laurent to the circulatory disturbances—to the increased distribution of blood. The action is soon ended, the alkaloids being eliminated by the urine rapidly.

Notwithstanding the freedom with which hyoscyamus and its alkaloid, hyoscyamine, are given, rarely are there any unpleasant effects. Empis, however, has reported some cases in which toxic symptoms happened from medicinal doses. These must have been examples of idiosyncrasy, for in the discussion which ensued, Joffroy, Damaschino, and others, expressed themselves strongly against the probability of serious effects from doses within safe limits.