Sulphate of Magnesia. MgO, SO3 + 7HO. Epsom Salts. Comp. 1 Eq. Magnesia=20, + 1 Sulphuric Acid=40, + 7 Water=63 = 123, Eq. Wt.

Med. Prop. and Action. Purgative, in doses of gr. cxx. - oz. j., dissolved in Oss. of Water, or Infusion of Senna. A smaller relative dose is required if the salt be largely diluted; thus, oz. ss. of the salt, in Oj. of fluid, acts quite as powerfully as double the quantity in only Oss. of fluid. It is a refrigerant purgative, lowering the force of the pulse, and producing a small degree of depression. It is apt to produce flatulence, to avoid which it should be given in some aromatic water. If it excite vomiting, this may generally be obviated by the addition of a few drops of dilute Sulphuric Acid; it is best given in combination with Senna, whose purgative effect it promotes, at the same time that it modifies its griping tendency. The Compound Infusion of Roses is a good vehicle for its administration. It is supposed to operate chiefly on the duodenum. By moderate exercise in the open air, while taking this salt, its purgative operation is diminished, and its diuretic effect increased. Dr. O'shaughnessy* judiciously directs that it should not be administered during the prevalence of Cholera, as it is apt to occasion too profuse and exhausting evacuations, and thus to bring on an attack of that disease. I have generally observed that natives, and inhabitants of the tropics, bear the operation of Epsom Salts very badly; it induces in them a great depression of the system, and often exhausting purgation. It is best adapted for febrile and inflammatory attacks occurring in persons of a robust, plethoric habit. In small doses and freely diluted, it acts as a diuretic. It is an antidote in poisoning by the Salts of Lead and Barytes. It is sometimes added to purgative glysters.

Offic. Prep. Enema MagnesiAe Sulphatis (Sulphate of Magnesia oz. j.; Olive Oil fl. oz. j.; Mucilage of Starch fl. oz. xv.).

Dose of Sulphate of Magnesia: as a purgative, gr. cxx. - oz. j.; as a diuretic, gr. xx. - gr. xl., freely diluted.

Incompatible*. Alkalies; the Carbonates; Lime Water; the Chloride of Calcium; and Acetate of Lead.

1769. Therapeutic Uses

In obstinate Constipation, a mercurial purgative, followed in a few hours by Magnes. Sulph. oz. ss. in Infus. SennAe Oss., is often very effectual. (See sect. 1493.)

1770. In Dyspepsia, accompanied by Costiveness, the Sulphate of Magnesia, in small doses, has been found very effectual. The best mode is to dissolve oz. j. in Oiss. of Infusion of Gentian or Quassia, with the addition of fl. drs. ij. of Aromatic Spirit of Ammonia, and of this to drink a wine-glassful every morning fasting. Mr. Langston Parker speaks favourably of the following mixture: - ℞ Magnes. Sulph. 3vj., Magnes. Subcarb. 5iss., Yin. Aloes f3vj., T. Humuli f3ij., Acid. Hydrocyan. Dil. exv., Infus. CascarillAe fvij., M. sumat. coch. amp. iij. bis in die.

* Beng. Pharm., p. 337. On Diseases of the Stomach.

1771. In Febrile And Inflammatory Diseases, It Is Particularly Serviceable

Dr. Christison * speaks highly of the following combination as a purgative in fevers: - ℞. Magnes. Sulph. iss., Ant. Pot. Tart. gr. ij., Aq. fxij., M. Of this, fij. - fiv. should be given every one or two hours, according to the effect produced. The refrigerant sedative action of this is often unequivocal. In the later stages, particularly if the fever assume a typhoid character, this formula should be modified.

1772. In Puerperal Intestinal Irritation, it is desirable to relieve the diarrhoea, which so often accompanies this state, otherwise it induces great debility. For this purpose, Dr. Locock states that he has often found advantage from occasional very small doses (gr. viij. - x.) of Magnes. Sulph. in an aromatic water, with v. - vj. drops of T. Opii; Chalk Mixture, Catechu, &c, are inadmissible.