Source and Composition. The full-grown fruit of Conium maculatum, the Spotted Hemlock, (nat. ord. Umbelliferae), gathered while yet green. It contains a liquid, volatile alkaloid, Coniine,—also Methyl-coniine in varying proportion,—a solid alkaloid, Conhydrine,—a volatile oil, and Coniic Acid.
Preparations. The Extracts are usually inert.
- Extractum Conii, Extract of Conium,—Dose, gr. ij-v-xl.
- Extractum Conii Fluidum,—Dose, ♏ij-v-xl.
All Conium preparations are uncertain, the active principle being very volatile. Each sample should be tested before fixing on its dose, and should have the characteristic mouse-like odor.
- *Coniïna, Coniïne, C8H15N, the active alkaloid,—Dose, ♏1/10-iij, or gr. 1/60-1/10. If given hypodermically, it must be neutralized by acetic acid, as shown by the use of litmus paper, otherwise it is too irritant; or the Hydrobromate in solution, gr. viij ad ℥j,—of this ♏x = gr. 1/6. This salt may be used in doses of gr. 1/12-gr. j, as it is not actively toxic.
- *Melhyl-Coniïne, C8H14NCH3,—affects the action of the plant, but is not used in medicine.
Physiological Action. Conium is a gastric irritant, producing nausea and vomiting. The main action of Coniïne is that of a paralyzant to the motor nervous system, beginning at the peripheral end-organs and extending upwards, involving the nerve trunks and finally the centres. Methyl-coniïne acts similarly but reversely, affecting the centres first; especially those in the spinal cord, causing paralysis of reflex action. Conium also blunts the common sensibility. Its prominent symptoms are-numbness and weakness of the legs, drooping eyelids, diplopia, slightly dilated pupils, vertigo, impaired utterance, slow and labored breathing, and death by paralysis of the muscles of respiration. The heart is not affected; and the mind is clear until CO2 narcosis sets in, but is torpid and indifferent. Socrates was poisoned by the juice of Conium, which was the state poison of the Athenians.
As the action of Coniïne and Methyl-coniïne vary considerably, and as the relative quantity of each alkaloid in the plant also varies, the results obtained from different samples of Conium, differ in marked degree, and are often contradictory of each other.
Toxicology. The antidote is Tannic Acid, which is chemically incompatible. Nux Vomica and its alkaloids, also Picrotoxin and other tetanizers, are antagonistic. Active exercise will antagonize the full development of its toxic action.
Therapeutics. Conium is used as a sedative to pain and to correct excessive motility. Large doses are required, as some physiological action is necessary. Children bear it well. In—
- Chorea,—it palliates by depressing the motor nervous system.
- Whooping cough and other spasmodic affections,—it is usefully employed.
- Acute Mania,—to quiet motor excitement and prevent exhaustion, Coniïne, ♏ss-iij, or hypodermically, ♏1/10, increased until some physiological effects are produced. Morphine given conjointly acts well.
- Pain and Spasm coexisting,—are well met by Conium.
- Cancer,—Conium is used locally and internally, to relieve the pain.
- Tetanus,—for its sedative action, Conium has been much used, but is inefficient.
- Blepharospasm,—is relieved by it, in 10-minim doses of the fluid extract.
- Epilepsy, Hysteria, Hystero-epilepsy, and most convulsive disorders,—it is of decided value, and can be given without fear of inducing a drug habit.
A Compend of Materia Medica, Therapeutics, and Prescription Writing, 1902, by Sam'l O. L. Potter, M.D., M.R.C.P.L.