This section is from the book "Botanic Drugs Their Materia Medica, Pharmacology and Therapeutics", by Thomas S. Blair. Also available from Amazon: Botanic Drugs, Their Materia Medica, Pharmacology and Therapeutics.
Henbane, Hyoscyamus niger. The leaves are universally official; the seed in Denmark, France, Mexico, and Spain.
First read what was said under "Belladonna" and note that atropine and hyoscy-amine are pharmacologically alike, and that hyoscine and scopolamine are also similar. So, then, pharmacologically, atropine and hyoscine are the two dissimilar alkaloids. The discussion of atropine, q. v., practically covers the subject, and it only remains to say that hyoscine (scopolamine) is an alkaloid of the atropine group in which the narcotic effect predominates. Hyoscyamus has a shorter stimulant action than has belladonna, and it is more narcotic, though it acts more like belladonna than like opium.
Whole-plant products are standardized according to the percentage of the combined mydriatic alkaloids. There should be more discriminating requirements.
Hyoscyamus is not so toxic as is belladonna and may be used with a greater measure of freedom. To quite a degree it replaces opium quite logically for the relief of pain, especially when due to spasm. The drug is not regarded as being habit-inducing in effect; it does not markedly inhibit the function of any organ, not even that of the kidney; it does not lock up the bowels. From the above it would appear that hyoscyamus is really a valuable agent.
Rather fortunately, although hyoscyamus contains hyoscyamine, scopolamine, and atropine (practically the antagonists, hyoscine and atropine), which are markedly toxic drugs; and, also, while the relative proportions of these two antagonists vary in the crude drug, yet, despite these facts, the natural association in the plant structure is such as to make the whole drug safe and comparatively efficient. But it must be remembered that hyoscyamus does not possess an opium action; it is in pain due to spasm that it acts effectively. Two illustrations will suffice. Griping is caused by an intestinal spasm due to nervous stimulation. Hyoscyamus acts almost specifically in relieving griping, hence extract of hyoscyamus is often incorporated in purgative formulae. Vesical spasm is exceedingly painful, yet hyoscyamus promptly relieves it because of its marked sedative action on the urinary unstriped muscle. To a lesser degree, spasmodic cough is relieved, hyoscyamus often being quite well substituted for codeine. The cough of tuberculosis is often relieved by hyoscyamus. So, as a sedative antispasmodic, hyoscyamus is adapted to the treatment of vesical tenesmus, chordee, and many other genitourinary affections, and to some pulmonary disturbances.
In its action on the nervous system hyoscyamus is more or less erratic. Hyoscine is exceedingly useful in quieting mania in the wards of a hospital for the insane, yet in the exigencies of private practice it may excite in place of quieting an explosive nervous outbreak. Yet in hysteria and delirium hyoscyamus - sometimes hyoscine - may serve a very useful purpose. One must always use these drugs with care in the field of neurology. Sometimes even the tremors of paralysis agitans are relieved by hyoscyamus, though rarely. On the other hand, it often fails in a purely functional hysterical attack. Some cases of insomnia are really cured by it, while many more cases are not at all favorably influenced.
So, then, in nervous diseases, hyoscyamus and its alkaloids are drugs of possible recourse, not ones of primary importance. When they do act, they influence the patient quite definitely for good or bad. The trouble is that it is quite as apt to be the latter as the former. One has to begin very cautiously in any given case.
None of the mydriatic alkaloids should be used as a routine soporific. Nor should any be used as an analgesic except in spasmodic affections. These are powerful and often dangerous alkaloids. Hyoscine is almost purely hypnotic in action, possessing very little antispasmodic influence; but, hyoscine is not a safe hypnotic for routine employment. Hyoscyamine acts so nearly like atropine, though there are clinical points of dissimilarity, that one should no more over-use hyoscyamine than he should atropine. Scopolamine is almost identical with hyoscine. Its now largely discredited vogue in the so-called "twilight sleep" brought it into undue notice. Physicians who care to run the risk of "twilight sleep" methods should first carefully study special books upon the subject.
The tincture is given in doses of 5 to 20 minims; the extract, in an average dose of 1 grain; the fl., in doses of 1 to 5 minims, average 3 minims. The alkaloids are: Scopolamine hydrobro-mide U. S. P. (average dose, 1-200 grain), hyoscine hydrobromide (8th Rev., av. dose 1-128 grain), hyoscyamine hydrobromide, U. S. P. (av. dose, 1-200 grain), and hyoscyamine sulphate (8th Rev., av. dose 1-128 grain). Note the tendency of the U. S. P. IX for lower dosage.
Merck's Manual lists hyoscine (from various solanaceae). Dose for insane, 1-30 grain; for sane persons, 1-400 to 1-200 grain. Hydrobromide in same doses. Hyoscyamine alkaloid (from hyoscy-amus) in crystalline form. Dose for insane, 1-8 to 1/4 grain; for sane persons, 1-120 to 1-30 grain. An amorphous form of this alkaloid is in the form of a syrupy liquid, and is used in doses of 1-8 to 34 minim. And a sulphate of the amorphous alkaloid is used in doses of 1-8 to 1/4 grain, whereas the sulphate of the crystalline alkaloid is only 1-120 to 1-30 grain in dosage.
Scopolamine hydrobromide (Merck), dose 1-240 to 1-60 grain; for general anesthesia, 1-100 to 1-60 grain with 1-6 grain morphine hydrochloride, every hour for three doses.
Some of the gentlemen who are so enthusiastic over the use of the alkaloids should note the differences, especially in dosage, between the U. S. P. and some of the nonofficial products. It may be they think they are using the potent U. S. P. products, whereas they are not.
There are alkaloids and alkaloids, just as in a lot of other uncertain things in this world. Better adhere strictly to the U. S. P. product in the occasional case in which it is wise to give one of the mydriatic group of alkaloids.
Euscopal is an optically inactive scopolamine hy-drobromide. Hypnotic, but is not active in checking secretion and dilating the pupil. Dose, 1-200 grain.
Scopolamine Stable, or Scopomannit, comes in ampules ready for use. Follow dosage given in the circular.