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.
Only two salts of this metal are officinal:
Lithiae Carbonas. - Carbonate of Lithia. L2CO3.
Characters. - A white powder, or minute crystalline grains; alkaline. Solubility, 1 in 100 of water.
Impurities. - Lime, alumina; detected by lime-water. Deficiency of lithia; detected by weight of residue.
Dose. - 3 to 6 gr., in 3 or 4 oz. of aerated water.
a. Liquor Lithiae Effervescens. - Effervescing Solution, of Lithia. Lithia Water. Made like Potash Water. 10 gr. to 1 pint. Lose, 5 to 10 fl.oz.
Characters. - A white amorphous deliquescent powder. Solubility, 1 in 2 1/2 of water. Dose, 5 to 10
Externally, lithia may be used as a fomentation in gout.
Internally, lithium has doubtless an antacid action on the alimentary canal very similar to that of potash, but it is not used for this purpose directly.
Lithium enters the blood, and behaves there much like potash, increasing its alkalinity, and combining with such acid bodies as uric acid, for which it has a powerful affinity, (1 part of a solution of the carbonate of lithia, at 38° C, dissolving four parts of the acid). It is extensively used in gout, to hold this substance in solution, and thus prevent acute attacks by fresh deposit in the tissues.
In this respect also lithia closely resembles potash, being a cardiac and nervo-muscular depressant, if given in large doses or for a length of time; but the risk of lithia poisoning is too small to be allowed to interfere with the exhibition of the drug in suitable cases.
Lithium is rapidly excreted by the kidneys, and probably by the mucous membranes. It is a powerful diuretic in passing through the renal epithelium; and whilst increasing the volume of water, it diminishes its acidity, and holds in solution even an excess of uric acid. It is accordingly used as a valuable remedy in gout, as it hastens the excretion of the products which it dissolves in the blood; and in acid lithiasis or gravel, where it prevents the deposit of salts in the kidney and urinary passages.
Both of the salts of lithia may be used, the only important difference between them being with respect to their solubility, which is very marked.