This section is from the book "Materia Medica Pharmacy, Pharmacology And Therapeutics", by W. Hale White. Also available from Amazon: Materia Medica Pharmacy, Pharmacology And Therapeutics..
Potassii Bicarbonas. Potassium Bicarbonate. Khco3 = 99.88.
Pass Carbon Dioxide through a solution of Potassium Carbonate, and let the bicarbonate crystallize out. K2Co3 + Co2 + H2O = 2Khco,.
The carbonate, chlorides, and iron.
Dose, 5 to 60 gr.; .30 to 4.00 gm.
Potassium bicarbonate is too feebly caustic to be of any use for this purpose. Otherwise its actions are those of potash.
Potassium bicarbonate may be given before meals to stimulate the flow of gastric juice; and as it is a gastric sedative, it is useful in painful dyspepsia accompanied by a scanty secretion of gastric juice. The increase of the antiseptic acid secretion is valuable in cases of dyspepsia associated with fermentation in the stomach. It may be taken after meals if too much acid is secreted, and the patient suffers from acid eructations, especially if pain be present also; but it is better treatment to remove the cause of the dyspepsia. It is not a common remedy for dyspepsia, sodium bicarbonate being usually preferred. Either is beneficial when much mucus is present, for this is rendered less viscid by alkalies. It should not be used as an alkali in cases of poisoning by mineral acids, because of the evolution of carbon dioxide, gas. Bicarbonates are used in preference to carbonates, as the latter are far too strongly alkaline for the stomach. Potash water is often drunk as an effervescing water instead of soda water. It should be a half of a one per cent. solution of potassium bicarbonate in water, into which carbon dioxide gas under a pressure of four atmospheres has been passed.
Potassium bicarbonate circulates in the blood as the carbonate. It was formerly much used in rheumatic fever, but is now superseded by the salicylates. Probably it did no good. In gout it is given to increase the alkalinity of the blood, which contains an excess of uric acid, but there is no evidence that it benefits gout, and the many alkaline mineral waters used for this disease are efficacious because they dilute the plasma, and so render it more capable of holding uric acid in solution. Potassium bicarbonate is believed to be haematinic, that is to say, it is thought to increase the amount of haemoglobin; but as for this purpose it is usually given with iron, its haematinic power has not yet been proved.
It is not much used for its diuretic effect and its alkalizing power over the urine, as the vegetable salts are preferable.