This section is from the book "A Practitioner's Handbook Of Materia Medica And Therapeutics", by Thos. S. Blair. Also available from Amazon: A Practitioner's handbook of Materia Medica and Therapeutics.
Magnesium, Borocitrate. Antilithic and antiseptic in doses of I5 to 30 gr. Magnesii carbon as, U. S. P., in large doses is laxative (3i), or in small doses of 10 to 20 gr. is antacid, quite agreeable in action. These doses once an hour until a laxative effect is produced, constitute an excellent treatment in sick headache and nausea due to acidity. The granular effervescent citrate is well tolerated by an irritable stomach, and is preferable for a purely laxative effect. The glycerophosphate, in 3 to 6 gr. doses, is an excellent nerve tonic, but its solutions do not keep well. The hypophosphite in slightly larger doses is also useful in nervous debility. Care should betaken in combining it, since it explodes in contact with oxidizing agents. The muriate is employed in homeopathic practice in liver diseases with constipation characterized by sparse and knotty stools. Magnesii oxidum, U. S. P., is the light, calcined magnesia, and acts similarly (but in somewhat less dose) to the carbonate. It is a valuable alkali to neutralize concentrated acids when taken in poisonous doses. Average dose, 30 gr. Magnesii oxidum ponderosum, U. S. P., is the heavy, calcined magnesia. Action and dose similar to the light. The phosphate is given in small doses dissolved in hot water, in homeopathic practice, in neuralgic pains relieved by warmth and in enteralgia and flatulent colic. Magnesii sulphas, U. S. P., or "Epsom Salt," is a cathartic of great value in doses of 4 to 6 3. If given in hot solution a less quantity suffices. It should always be well diluted. Doses of 20 to 30 gr. are aperient. This agent is of supreme value in abdominal surgery, since it does not cause active peristalsis. It is of value in lead poisoning. Meltzer and Auer assert that 1 1/2 to 2 f3 of a 25% solution injected into the subarachnoidal space of the spinal cord produces motor paralysis and anesthesia in the portion of the body below the site of injection. The anesthesia comes on within four hours, and continues for several hours. The heart is not affected, although respiration is slowed. Intravenous injections are not so efficient. This old drug is coming to be recognized as a remarkable agent, and is being exploited in a number of new directions. The homeopaths use small doses of the pure salt or the IX trituration in diabetes and in conditions of the skin giving rise to warts. The effervescent salt is official. The sulphite is a valuable intestinal antiseptic, less disagreeable in taste than sodium sulphite. Dose, 5 to 30 gr.