This section is from the book "A Text-Book Of Pharmacology, Therapeutics And Materia Medica", by T. Lauder Brunton. Also available from Amazon: A text-book of pharmacology, therapeutics and materia medica.
The seeds of Colchicum autumnale, collected when fully ripe, usually about the end of July or beginning of August, and carefully dried, B.P. The seed of Colchicum autumnale, U.S.P.
Fig. 226. - Colchicum Seeds.
Tinctura Colcbici Seminum......54 1/2 gr. to 1 fl. oz.......
Extractum Colchici Seminis Fluidum..................................................
Tinctura ,, ,, ..............................................................
Vinum ,, ,, ..............................................................
General Action. - The action of colchicum does not vary in proportion to the dose, since, when a certain (fairly large) dose is given, an increased dose does not seem to produce a more marked effect. It acts as a poison both to cold- and warm-blooded animals, but its effect is least marked on cold-blooded animals, and more marked on Carnivora than Herbivora. It has the same effect on the alimentary canal whether swallowed or sub-cutaneously injected.
When given in continued non-poisonous doses it causes an acrid taste, with reflex flow of saliva, and symptoms of gastrointestinal disturbance, viz. irritation of the fauces, loaded tongue, loss of appetite, flatulence, uneasiness, or pain in the stomach and intestines, and diarrhoea. The pulse is slowed, and there is a tendency to muscular weakness.
A single large dose, or moderate doses long continued may produce symptoms of acute gastro-intestinal inflammation, viz. violent vomiting (vomited matter being first bilious and then bloody) and purging (the stools being first serous, then mucous, then bloody). Marked symptoms of collapse supervene, the pulse becomes small, rapid, and thready, the skin cold and bedewed with sweat, respiration slow and painful. Death ensues from collapse, the brain remaining clear to the last.
Sometimes nervous symptoms occur, such as flying pains over the body, numbness, and occasionally, though rarely, convulsions.
Special Action. - When applied to the skin it is an irritant, causing redness, prickling, and smarting, and if taken into the nose causes sneezing and running at the eyes.
Internally. - Its action on the brain, if any, is not well marked.
In frogs the spinal cord is paralysed, the paralysis being preceded by excitement, sometimes giving rise to convulsions.
In the higher animals there is no excitement, the cord being paralysed from the first. The sensory nerves are more or less paralysed. The motor nerves and muscles are unaffected. The circulation is affected, but the action is to a great extent reflex, since, if injected directly into the circulation, both the heart and the blood-pressure are only slightly altered. Very large doses are required to paralyse the inhibitory fibres of the vagus, but ultimately they are paralysed.
The Secretion of Urine. - Some authorities affirm that the total solids (both inorganic and organic) are increased, and also the quantity of water. Some say that only the urea is increased, others that the uric acid is increased, while others, again, contradict both these statements.
The probable explanation of these conflicting statements is that the observers have conducted experiments with different diets.
Treatment in Poisoning. - Evacuate the stomach by an emetic, if vomiting is not induced by the drug itself; give tannic acid in large quantities (which acts as a chemical antidote); white of egg diluted with water may be given freely; or, if the pulse is very depressed, give stimulants and keep the patient warm.
Uses. - Its chief use is in gout, in the form of vinum or tincture, either in large doses during the fit, or in small ones continued for a length of time. It seems to act best when the bowels are previously freely acted on, hence a very old and useful mixture is colchicum, magnesia, and sulphate of magnesium.
In rheumatic arthritis 10 min. of tincture with 10 gr. of potassium iodide often prove useful.
In subacute rheumatism it is of very much less service.
In acute rheumatism it is hardly ever used, salicylate of sodium being more frequently employed.