CARDIUM, DISEASES OF. HYDROPHOBIA. See RABIES. HYOSCYAMUS AND HYOSCINE.— Hyoscyamus (U. S. P.) is the leaves and flowering tops of Hyosegamus niger, or henbane, which is indigenous to the United States. The plant is an annual and belongs to the family of Solanacce. The fresh herb has a rank, heavy, sicken ing, unpleasant odor, which disappears on drying. The plant contains hyos cyamine, an active principle (alkaloid), which occurs as white, silky crystals, and also in an amorphous form, as a brown, syrupy liquid. From the latter Laden burg derived a new hyoscyamine. He found that hyoscine, hyoscyamine, and atropine were isomeric, having the same formula, and each being separable into tropic acid and tropine, or pseudotropine. Both hyoscyamine and hyoscine form salts with the acids.
Preparation and Doses.—Hyoscyamus, 5 to 15 grains.
Extract of hyoscyamus, 1 to 3 grains.
Extract of hyoscyamus, fluid, 3 to 10 minims.
Tincture of hyoscyamus, 10 to GO min ims.
Hydrobromate of hyoscine, to grain.
Hydrobromate of hyoscyamine, to grain.
Sulphate of hyoscyamine, to grain.
Physiological Action.—Its action on man is analogous to that of belladonna and stramonium, though milder. Chil dren can be given a larger dose than adults. Hyoscyamine, according to Gnauck and other observers, resembles atropine in its action upon the vagus and heart-muscle, though its effects are less marked and prolonged. It seems also to exercise an inhibitory influence upon the vasomotors, especially those of the abdominal vessels. It is an active soporific.
Study of the physiological action of hyoscine hydrochlorate upon cold- and warm- blooded animals. Upon the first, minute doses (less than grain) slow the action of the heart by stimulating the peripheral cardio-inhibitory appa ratus. Larger doses accelerate cardiac action, increase muscular contractility, irritability of spinal cord, and conduct ing power of motor nerves; they also slightly depress the excitability of pe ripheral sensory nerves. Still larger doses intensify these symptoms, lowering reflex action. Toxic amounts produce diastolic arrest, of heart, loss of reflexes and of function of both sensory and motor nerves, and finally cerebral paraly sis. On warm-blood animals, as dogs and
rabbits, hyoscine at first diminishes and afterward increases the cardiac beats by a primary stimulation and a secondary paralysis of the peripheral eardio-inbibi tory apparatus. Subsequently the drug diminishes the pulse by depressing_ the excitomotor apparatuses of the Heart. The pressure is increased through stimu lation of spinal and vasomotor centres; it is later depressed, owing to exhaustion of cardiac muscle. It retards respiration, diminishes secretion of saliva, depresses irritability of motor area of cerebral cor tex, and lowers panic sensibility. It causes prolonged dilatation of pupil, due to stimulation of sympathetic nerve. The drug has no action on peripheral or visceral temperature, nor does it acceler ate the process of deoxidation of the blood. Its action would seem to resemble that of atrophic, but it differs from this in that it depresses cerebral irritability. K. L. (London Med. Recorder, May 20, '90).
Clinical effects of hyoscine resemble in every way those of atropine. Gordon Sharp (Practitioner, Jan., '94).
Hyoseine in frogs first quickens and then slows respiration, while larger doses cause a condition of narcosis and paral ysis. In rabbits a dose of 3 grains only caused dilatation of pupils and quicken ing of the respiration; in cats and dogs the chief action is on motility; there ensue paresis of the extremities and ataxia; respiration is little affected, but there is marked mydriasis. The action on the circulation was slight, and none of the animals died, even after the large doses used. It antagonizes the action of muscarine on the heart, and is ex creted in the urine.
In man grain causes distinct symp toms, dryness of mouth, faintness, and somnolence, but in the insane much larger closes can be borne with perfect impunity. The toxic dose lies between and grain. Serious symptoms, such as coma, cyanosis, paresis, and twitchings have been observed. Wind scheid (Deutsches Arch. f. klin. Med., B. 66, '99).