Source and Composition. The rhizome and rootlets of Gelsemium sempervirens, a climbing plant of the nat. ord. Loganiaceae, indigenous in the Southern States. It contains an alkaloid, Gelsemine, in combination with Gelsemic Acid, also a volatile oil, and a resin. Dose, gr. ij-xx.
Preparations. Only two are official, viz.—
- Tinctura Gelsemii, ♏x-ℨj.
- Extractum Gelsemii Fluidum, ♏ij-xxx.
- *Gelsemina, Gelsemine,—with acids forms soluble salts. Dose, gr. 1/60-1/20.
Physiological Action. Gelsemium is an antispasmodic, a diaphoretic and nervous depressant, paralyzing motility and sensibility by central action on the spinal cord. It is also anaphrodisiac. In moderate doses it causes languor, slowing of the cardiac rate, feebleness of muscular action, impaired sensibility, drooping eyelids and dilated pupils, with some diaphoresis. A Toxic Dose (a teaspoonful of the fluid extract) produces vertigo, diplopia, drooped eyelids, dilated pupils (paralysis of 3d nerve), labored breathing, slow and feeble heart, dropped jaw, staggering gait, great muscular weakness and almost complete general anaesthesia, profuse sweats, loss of articulation, and death by asphyxia (paralysis of muscles of respiration.) Consciousness is preserved until CO2 narcosis sets in. Convulsions do not occur in man, but do in lower animals, the convulsive movements being backward. Motion is affected before sensibility in warm-blooded animals, sensibility before motion in frogs.
Gelsemium, though it lowers the heart rate, is not an arterial depressant, and does not irritate the gastro-intestinal tract, The effects of a moderate dose pass off in about three hours. It produces a decided lowering of the body temperature.
Antagonists. Morphine is the most complete antagonist, but Digitalis, Ammonia and Alcohol are also antagonistic. Emetics, heat to the body, artificial respiration and faradism of the muscles of respiration are measures of prime importance in poisoning by this drug.
Therapeutics. Gelsemium is indicated in conditions of exalted nerve function, and contraindicated when there is weak heart. It is well used in—
- Cerebro-spinal Meningitis,—♏v of the fluid extract every 2 hours.
- Mania, with great motor excitement and persistent insomnia.
- Delirium Tremens, and many forms of Insomnia,—it is efficient.
- Pneumonia and Pleuritis,—♏v-x of the fluid extract every 2 hours, to maintain a physiological effect, give excellent results. If the heart be weak this remedy must not be used.
- Cough of convulsive or spasmodic character,—it is useful.
- Neuralgia of the 5th Nerve has been successfully treated by Gelsemium.
- Remittent Fever,—it usually exercises a very beneficial influence.
- After-pains,—are frequently suspended by moderate doses of the tincture.
- Ovarian Neuralgia,—there is no better remedy, in full doses.
- Dysmenorrhoea,—Gelsemium often greatly alleviates the pain.
- Irritable Bladder of women, and incontinence of urine from spasm of the vesical muscular fibres,—this remedy is often very efficient.
A Compend of Materia Medica, Therapeutics, and Prescription Writing, 1902, by Sam'l O. L. Potter, M.D., M.R.C.P.L.