This section is from the "A Practical Treatise On Materia Medica And Therapeutics" book, by Roberts Bartholow. Also available from Amazon: A Practical Treatise On Materia Medica And Therapeutics
Many of these have been discussed elsewhere; some of them are no longer employed in medical practice. The sulphate and the citrate of magnesium may be regarded as typical representatives of the class, and hence, in a statement of their physiological actions and therapeutical applications, may be comprehended all that is of immediate and practical value on the subject.
Magnesium sulphate. Sulfate de magnésie, Fr.; Bittersalz, Ger. In colorless crystals, which slowly effloresce on exposure to the air, and are very soluble in water. Dose, 3 j— oz j.
A white, coarsely-granular salt, deliquescent on exposure to air, odorless, having a mildly acidulous, refreshing taste, and an acid reaction. Soluble with copious effervescence in two parts of water at 60° Fahr.; almost insoluble in alcohol. Dose, 3 j— 3 iv.
Solution of citrate of magnesia. Dose, oz iv— oz viij. A table-spoonful of the granular salt added to a half-tumblerful of water, and drunk during effervescence, is the quantity and the form in which it may also be taken. The bottled solution, which is also highly effervescent, must be drunk immediately on being poured out. It is a pleasant drink, and, when properly prepared, an active cathartic.
As a general rule, saline cathartics are easily borne by the stomach; especially is this true of the Epsom salts. The purgative action is due chiefly to increase of the intestinal secretions, and hence the stools are large and watery. Thiry and Radziejewski had apparently demonstrated that all purgatives acted by increasing the peristaltic movements, but exactly opposite results have been obtained by Moreau, whose observations have been confirmed by Vulpian and Brunton. The conclusion reached by the last-named observer is expressed as follows: "Such positive results as these seem to prove that purgatives do cause a flow from the intestinal wall, quite as conclusively as experiments with Thiry's fistula do the opposite; and, as the conditions under which the purgatives act on the intestines more nearly approach the normal in Moreau's than in Thiry's experiments, there can be little doubt that purgatives produce a decided secretion of fluid from the intestines, as well as accelerate peristaltic movements." Of the agents employed by Brunton in his experiments—croton-oil, elaterin, gamboge, jalapin, and sulphate of magnesia—the greatest secretion was caused by the latter. The results of the best directed experiments are, therefore, in accord with clinical observations, and it may hence be considered as established that saline cathartics produce an outpouring of fluid into the intestinal canal. This outward osmosis occurs chiefly from the vessels, and is not truly a secretion of the glandular appendages of the mucous membrane.
The saline purgatives are indicated in acute inflammatory affections, as a part of the denutrition treatment. If the arterial tension is abnormally high, purgatives, especially the salines, lower it, as the sphygmographic tracings show. When a considerable quantity of serum is withdrawn from the intestinal vessels, the blood-pressure is necessarily diminished elsewhere (Brunton). Free transudation from the blood-vessels of the intestinal canal lessens the amount of work which the kidneys have to do, and, if these organs are hyperaemic, removes the congestion. Saline cathartics are therefore very important remedies in the treatment of renal and cardiac dropsy. Free purgation, also, influences the condition of the kidneys by reflex action. As a result of the lessened hyperemia of the kidneys, the diminution of the blood-pressure, and the reflex stimulation of these organs, the action of a purgative is often followed by greatly-increased activity of the renal function. In ascites from obstruction of the portal circulation, saline cathartics are even more conspicuously beneficial than in general dropsy—for in this case they affect directly the organs involved. Cholaemia, uraemia, oedema of the brain, increased intracranial blood-pressure from any cause, are conditions requiring the use of active saline cathartics.
The most important applications of saline cathartics are in the treatment of various intestinal disorders. When the stomach is irritable, and the intestines inflamed, no other purgative is so well borne as Epsom salts, and its use may be resorted to when any other agent of the kind would be inadmissible. Impaction of the caecum, and typhlitis resulting from this cause, may be removed by the proper administration of this remedy. It is unsafe, by active and drastic purgatives, to attempt to unload the bowel—for these harsh measures will only aggravate the existing inflammation. Epsom salts will liquefy the fecal masses and deplete the vessels, and thus remove the obstruction without causing any irritation. Small doses frequently repeated are more suitable than a large purgative dose. Usually about a tea-spoonful in a wineglassful of water, every three hours, will be the quantity required. Perityphlitis and the peritonitis arising from inflammation and perforation of the appendix vermiformis are conditions in which purgatives of any kind are inadmissible.
The constipation which accompanies lead-colic can be overcome by Epsom salts. Rx Magnesii sulphatis, oz j; acidi sulphuric, dil., 3 j; aquae, oz iv. M. Sig.: A table-spoonful every three hours. As Brunton has pointed out, the administration of Epsom salts is a very important expedient in the treatment of the saturnine cachexia. Lead, as well as other minerals, mercury and copper, for example, is eliminated with the bile, and is discharged into the intestine, where it is again absorbed. For an indefinite period, therefore, the absorption and discharge of the same metal may be going on; and hence the utility of giving purgative doses of Epsom salts during the treatment of lead-poisoning.
The most efficient treatment of acute dysentery is by the administration of sulphate of magnesia. It is especially adapted to the acute stage when there are fever, pain, tenesmus, and stools of mucus and blood. It lessens the hyperaemia and causes fecal evacuations, with the result of relieving the pain and the distressing straining. It is administered as follows: Take a sufficient quantity of sulphate of magnesia to saturate eight ounces of water, and to this saturated solution add one half ounce of diluted sulphuric acid. The dose of this is a table-spoonful every hour or two, in a wineglassful of water, until it operates. Sulphate of morphine may be combined with it, or starch enemata with laudanum may be employed.
The bleeding from haemorrhoids may sometimes be arrested by the above-described solution of Epsom salts and sulphuric acid, especially if the state of the haemorrhoidal vessels be due to constipation. Uterine haemorrhage caused by the presence of a fibroid, or by subinvolution, and congestion of the pelvic viscera, are not infrequently relieved by the same agent when other agents apparently more powerful fail. When congestion of the pelvic organs, constipation, and anaemia coexist, the following is an efficient remedy: Rx Magnesii sulphat., oz j; ferri sulphat., manganesii sulphat., āā Э j; acid, sulphur, dil., 3 ij; aquae, oz iv. M. Sig.: A table-spoonful in a wineglassful of water each morning before breakfast. For habitual constipation in those of full habit and active circulation, a daily morning dose of a tea-spoonful of Epsom salts is often a permanently effective remedy.
The disagreeable taste of Epsom salts is perfectly well covered by coffee. Boil for two minutes in an earthen vessel one ounce of sulphate of magnesia and two and a half drachms of roasted coffee in a pint of water; then remove from the fire, allow it to "draw" for a few minutes, and strain.
The other saline purgatives belonging to this group are:
Sodii Sulphas, sulphate of sodium, Glauber's salts,
Potassii Sulphas, sulphate of potassium; but both of these have long since ceased to be used.
Sodii Phosphas, phosphate of soda,
Potassii et Sodii Tartras, tartrate of potassium and sodium, Rochelle salts, and
Pulvis Effervescens Compositus, effervescing aperient powders or Seidlitz powders, have been considered elsewhere.
Potassii Bitartras, bitartrate of potassium, cremor tartar, may also be regarded as a member of this group, although it has but feeble purgative property.