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.
Lithia salts act much like the alkalies upon the gastric secretions, - the carbonate especially is a direct antacid. Small doses are readily borne, but doses of 30 to 50 gr. of carbonate - such as were used by Charcot - give rise, after a few days, to cardialgia and dyspepsia (Note to French edition of Garrod on Gout). Rabuteau also states, that though he, at one time, recommended 15 to 30 gr. per diem, his later experience proved that dyspepsia and even vomiting were caused by these quantities. Climent records similar results in his own person ("Traitement de la Gravelle, etc.," These, Paris, 1874), and although lithiated waters - e.g., at Baden-Baden - at first improve appetite and digestion, they quickly give rise to sickness and diarrhoea if taken in excess (Althaus).
Carbonate of lithia increases the alkalinity of the blood more quickly than potash or soda compounds (Garrod). The same salt, given in large doses (80 gr.), rapidly diminishes the number of red blood-corpuscles, and induces ana?mia, like the alkaline carbonates (Climent, op. cit.). A much less quantity than 80 gr. seems to exert a depressant effect on the heart in weakly subjects - lithia in this respect, again, resembling potash in its action - but it does not depress so much as that salt (Garrod). Several observers agree in the conclusion that bromide of lithium, a salt with especially sedative powers, exerts a less lowering effect upon the heart than bromide of potassium (Roubaud: Archives Gen., i., 1875, Levy, These, Gazette Medicale de Paris, 1875, No. 27), but frogs and some warm-blooded animals may die under toxic doses of lithia, with cardiac arrest in diastole (Husemann, Hesse).