Properties : Calcium chlorid occurs as white, translucent fragments, which are odorless and have a sharp saline taste. It is very deliquescent and should be kept in well-stoppered bottles. It is freely soluble in water (1 : 1.3) and also in alcohol (1 :8).

Incompatibilities: Soluble carbonates, phosphates and sulphates produce a precipitate of the corresponding insoluble salts of calcium.

Action and Uses: The chlorid is more irritating to the stomach than other salts of calcium and it should always be given well diluted. It is absorbed slowly and imperfectly; in the intestine it may be converted into the insoluble carbonate or phosphate, and the greater part of the calcium is excreted in this form. Calcium salts are sedatives to muscle and nerve action when absorbed. A lack of calcium in the tissues is believed to be a factor in the development of nervous irritability, tetany and other forms of convulsions. Large intravenous doses of calcium act somewhat like digitalis. It is also believed to increase the coagulability of the blood under certain conditions, but not often. These effects, however, are not produced when calcium is given by the mouth. There is no lack of calcium in the system under ordinary diet. It is therefore doubtful whether calcium chlorid has much if any systemic action when administered by mouth. It is used, however, in hemophilia, typhoid fever and other hemorrhagic conditions, with the idea of increasing the coagulability of the blood. Direct observations of the coagulation time have given contradictory, but generally negative results. The clinical evidence is not very strong, but the drug is at least harmless. Calcium chlorid is also administered, apparently with benefit, against urticaria and serum rashes.

When injected directly into the blood, calcium 6alts depress the nervous and muscular systems, while the inactivation of calcium by the injection of oxalates and citrates produces convulsions. This is the basis of an as yet unproved hypothesis that certain forms of nervous irritability are due to disturbed calcium metabolism.

Dosage: 0 5 gm. or 7 grains. Calcium chlorid is best administered in dilute solution sweetened with syrup or elixir.