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.
Yellow Jasmine, Gelsemium sempervirens. Official in England, Japan, Mexico, Switzerland, and the U. S.
There are two alkaloids, gelseminine and gelsemine, only the first-named being of importance.
In toxic doses gelsemium produces paralysis of both motion and sensation, in rare instances affecting the mind. After motion is destroyed, respiration becomes labored and finally the respiratory center is paralyzed. The toxic dose of gelsemium varies within rather wide range, poisonous results sometimes occurring quite unexpectedly. I have very largely used the drug in my practice and have had occasion to observe unexpected toxic effects.
Physicians should be cautioned against the use of large doses except in sthenic cases kept under observation. In my experience, these toxic effects may develop slowly, often hours after administration. Warning symptoms are ptosis, double vision, dilated pupils, weakness and depression. In threatening cases give digitalis and atropine, according to Hill; but some writers contend that morphine serves better than atropine. I secured good results from the copious use of strong boiled tea, the tannin therein being effective. One fluidrachm of the fl. may readily cause death. I have observed dangerous symptoms from thirty minims, taken in mistake for the tincture.
Gelsemine, the minor alkaloid, has no well-defined action in the mammal. Gelsem-inine has an action almost identical with that of coniine, differing in the paralytic effect on the centers being greater with gelseminine than with coniine, and the effect on the motor terminations being less with gelseminine than with coniine. The sphincters of the pupil and the ciliary muscle are paralyzed if the drug is applied to the conjunctiva, but only in doses of marked toxicity is this effect produced through the general circulation. See "Conium."
The circulation is not influenced in any way, suggesting a therapeutic action similar to that of aconite or veratrum. Blood-pressure is not influenced and the only definite effect is a paralysis of the inhibitory mechanism of the heart.
Gelsemium is not a safe remedy in large dosage. As such doses are necessary to secure its mydriatic action, any definite influence upon severe convulsive disorders, or to accomplish much as a circulatory depressant, the drug should never be used in place of the agents of the belladonna group, either to produce mydriasis or the antispasmodic effects of this group; it should not be used in the treatment of tetanus, chorea, etc., and it should not be used in the place of aconite in the treatment of cardiac and cardio-vascular conditions, or in the treatment of fever in general, though it is a valuable auxiliary in the management of some febrile conditions.
The true role of gelsemium may be said to be wholly directed to the nervous system, 1st, in certain neuralgic conditions; 2d, in cerebral hyperemia, especially with irritated centers; and 3d, as a terminal antispasmodic. These indications are arrived at partly from the pharmacology and partly from clinical experience. They depend upon the initial and not upon the toxic properties of the drug, and they are met by comparatively small dosage. Even here, the drug is contraindicated when, as has been well said by Felter, "the eyes are dull, the pupils dilated, and the circulation feeble. Under these circumstances it is poisonous even in small doses."
Trigeminal neuralgia, especially of its facial branches, responds unusually well to gelsemium. Nervous headache, often really neuralgic or from eye-strain, responds in many cases. True intercostal neuralgia does not yield readily, although the pain of pleurodynia, often thought to be neuralgia, comes under the influence of small and frequent doses. Neuralgia due to hyperemia of the brain and cord is benefited; that due to organic changes and toxic influences is not relieved.
Cerebral hyperemia occurs symptomatically in many conditions, and in some fevers. In functional cases gelsemium may be a main or an adjuvant remedy, due to the sedative effect upon the cerebrospinal centers - other words, the coniine action. If the irritation is partly vascular, aconite combines well with gelsemium - high blood-pressure; and gelsemium sometimes cooperates with the bromides or hydrated chloral; but be very careful here; you are dealing with two-edged tools. The cases of hyperemia in which it is indicated have bright eyes, contracted pupils, and are restless. These cases may range from delirium tremens to central irritation from teething, and several of the fevers may manifest them. Remember that gelsemium is purely a symptomatic remedy in these hyperemic cases, and it requires considerable discrimination to use it wisely; this is attained only by clinical experience. Always watch the case; it is the case, not the specifically named disease, you are treating with gelsemium. Don't expect to appreciably reduce fever with this drug, used alone.
As a terminal antispasmodic, some cases of hysteria are amenable to it - active and reflex ones. Spasmodic conditions of the urinary tract, spasmodic dysmenorrhea, ovarian neuralgia, uterine colic, and irritable sphincters are often amenable. Don't give it in labor; it may be provocative of post-partum hemorrhage.
refer a fl. made from the recent material, not the dried drug. Ordinary dosage of this is one to two minims, rarely over five minims. The U. S. P. average dose in only 1/2 minim, which I consider low. Small doses may be given frequently. Neuralgic cases may require 5 minims of the green-drug fl. (or gelseminine, 1-120 to 1-60 grain - rarely). Average dose, tr. 4 minims; maximum safe, 30 minims. Average dose fl. from dried drug, 1/2 minim.