This section is from the book "Materia Medica And Therapeutics: An Introduction to the National Treatment of Disease", by John Mitchell Bruce. Also available from Amazon: The pharmacology and therapeutics of the materia medica.
Externally, green hellebore and veratria are first powerfully irritant and then depressant to the nerves and vessels, causing pricking, burning sensations, and redness of the skin, followed by loss of sensibility and vesication. Unguen-tum Veratriae is therefore applied to relieve neuralgic and rheumatic pains, but the alkaloid is absorbed by the unbroken skin, and may produce its powerful specific effects.
Inhaled or sniffed into the nose, these substances cause violent sneezing and cough, manifestly from irritation of the nerves. No use is made of this property.
Internally, reflex salivation, dysphagia, epigastric heat and pain, vomiting, and diarrhoea, indicate the irritant effect of veratrum viride and veratria on the alimentary canal. They are never given as emetics.
Veratria enters the blood rapidly from the skin or mucous surfaces. Leucocytes (out of the body) are paralysed or killed by dilute solutions of the alkaloid.
Veratria may be found in the various organs after administration. Full doses produce, in addition to the painful vomiting of local origin, great muscular prostration, faintness, and finally collapse, preceded and accompanied by a slow feeble or irregular pulse, feeble respiration, cold sweats, fall of temperature, occasional muscular twitching and creeping, and itching sensations on the skin. It has now been proved that these phenomena are not referable to the cerebrum, which remains unaffected, with perfect consciousness, nor to the motor centres of the cord or motor nerves, all of which are but slightly depressed. The muscles are the organs attacked by veratria, which produces a highly remarkable lengthening of the contraction, the descending portion of the muscle curve (phase of relaxation) being fifty times its ordinary length. Therewith the force of the contraction is increased. These two effects on the muscle contraction are so marked that the muscle appears to be in a state of tetanus, but the curve is really a single contraction, and not compound or a fusion of closely repeated simple spasms. Larger doses cause weakness of the muscles and finally paralysis.
The heart, after primary acceleration, is affected just like the voluntary muscles, its contractions becoming greatly lengthened, and thus its frequency reduced (even by 20 to 60 beats per minute in fever), long pauses occurring at the end of systole. Irregularity, acceleration with feebleness, and finally paralysis are the result of larger doses. The blood pressure rises at first, falls during the stage of infrequency, and is then dangerously lowered. The primary stimulation of the heart and vessels, and part of the succeeding depression, occur through the centres in the medulla.
Respiration is first accelerated, then slowed, and finally arrested through the centre, the muscles, and the pulmonary vagus; the movements exhibiting expiratory pauses and irregularity.
The fall of temperature, which may amount to several degrees in fever, appears to be referable to the circulatory failure.
The specific uses of veratria depend on its depressing action on the heart, vessels, and body temperature; that is, it is a powerful antipyretic. It has been recommended for the same conditions as aconite, namely, acute febrile processes in strong subjects, such as sthenic pneumonia and acute rheumatism. If it be considered safe and desirable to treat such cases with powerfully depressant measures, veratria may be used; but in England, at least, the opposite line of treatment is generally followed, and every lowering influence on the heart carefully avoided. In aneurism and in haemorrhage, where the blood pressure has to be reduced, veratria cautiously given, or the Tinctura Veratri Viridis, may he of much service.
Veratria quickly appears in the urine, being excreted by the kidney.
Colchici Cormus- Colchicum Corm. - The fresh corm of Colchicum autumnale; collected about the end of June; and the same stripped of its coats, sliced transversely, and dried at a temperature not exceeding 150°.
Characters.-Fresh corm about the size of a chestnut, flattened where it has an undeveloped bud ; furnished with an outer brown and an inner yellow coat; internally white, solid and fleshy; yielding when cut a milky acrid and bitter juice. Dried slices about a line thick, moderately indented on one, rarely on both sides, firm, flat, whitish, amylaceous.
Substances somewhat resembling Colchicum: Tragacanth and Squill, which have different texture, and are not kidney-shaped.
Lose.-2 to 8 gr. in powder.
Colchici Semina- Colchicum Seeds. - The fully ripe seeds of Colchicum autumnale.
Characters.-About the size of white mustard seed, very hard, and of a reddish-brown colour.
Substance resembling Colchicum Seeds: Black Mustard, which is smaller.
Composition. - Colchicum contains an active principle, colchicin, C17H19NO5, an amorphous, yellowish, bitter alkaloid; with tannic and gallic acids, starch, sugar, gum, etc.
a. Of Colchici Cormus:
Extractum Colchici. 25 in 1. The expressed juice of fresh Colchicum Corms, decanted from deposit; heated to 212° Fahr. to coagulate albumen; strained; and evaporated. Dose, 1 to 3 gr.
Extractum Colchici Aceticum. 18 in 1. Made like the simple extract, Acetic Acid being first added to the crushed corms. Dose, 1/2 to 2 gr.
Vinum Colchici. 1 dried in 5. Dose, 10 to 30 min.
b. Of Colchici Semina:
Tinctura Colchici Seminum.-1 in 8. Dose, 10 to 30 min.
The physiological action of colchicum is imperfectly-understood, and affords but a partial explanation of its empirical use.
Given internally it is a gastro-intestinal irritant, acting as an emetic and purgative in full doses, the stools containing a decided increase of bile, partly referable to a direct cholagogue effect of the drug. Colchicin appears to enter the blood and tissues, and here acts chiefly upon the central nervous system. The convolutions and spinal cord are depressed, large doses causing loss of sensibility and consciousness, and diminished reflex excitability. The peripheral sensory nerves are also paralysed, but the motor nerves and muscles remain unaffected. The respiratory centre is lowered in activity, and death occurs by asphyxia. The heart is weakened, the pulse even becoming intermittent; but this effect is believed to be entirely secondary to the disturbance of the respiration. The kidneys are hypergemic, and the amount of urine diminished; the uric acid and probably the urea are reduced in quantity. The skin perspires more freely.
Colchicum is chiefly used to relieve the pain and inflammation, and shorten the duration, of acute gout, for which purpose it is usually given in doses short of producing the above physiological effects, so that the mode of its action is quite obscure. It is most successful in first attacks in young robust subjects; less useful, and to be used with caution, in the chronic gout of old weakly individuals; and occasionally it completely fails to afford any relief. It is generally prescribed with alkaline purgative salines. In some acute gouty affections of other parts than the Joints, such as bronchitis, hepatic congestion, neuralgia, ana urethritis, colchicum occasionally relieves. It is worse than useless in rheumatism. The extract may be added to purgative pills as a cholagogue.