This section is from the book "Materia Medica And Therapeutics Inorganic Substances", by Charles D. F. Phillips. Also available from Amazon: Materia medica and therapeutics.
In cases of excessive secretion of uric acid, potash salts are useful by assisting oxidation of the acid to some extent, and also by furnishing a base with which the acid is readily eliminated in a soluble form; they should be considered, however, rather palliative than curative, and attention should be equally directed to diet and hygiene during their use.
The continued administration of potash had, at one time, much reputation in the treatment of uric acid calculus, and Dr. William Roberts (Manchester) has shown, by careful experiments, that benefit may be expected from it under certain conditions. It is specially adapted for renal calculi which cannot be reached in any other way, and for small vesical calculi consisting either of uric acid or of cystine. The acetate and citrate of potash are the best to use, and in order to secure a sufficient and continuous alkalescence of the urine, 30 gr. for children, 40 gr. for adults, of either salt must be taken at intervals of about three hours. This quantity will give to the urine an alkalinity equal to 3 or 4 gr. of carbonate in the pint, which may be kept up for several weeks without injury to the general health, but the urine must be frequently examined, and if it become ammoniacal the treatment should be omitted.
As an illustration of its occasional value may be cited the case of the Rev. V. Harcourt, who, at the age of eighty, continued it for three months, rendering the urine alkaline to the extent of 20 to 25 gr. per pint, with relief to many painful symptoms, and with much advantage (Medical Times, ii., 1869). For phosphatic calculi, potash is, of course, unsuitable.