This section is from the "A Handbook of Useful Drugs" book, by State Medical Examining and Licensing Boards.
Properties : Silver nitrate, AgN03, occurs in colorless, crystal-line tables, becoming gray, or grayish black on exposure to light in the presence of organic matter. It is odorless and has a bitter, caustic, and strongly metallic taste. It is very soluble in water and soluble in alcohol.
Incompatibilities: Silver nitrate is incompatible with soluble chlorids, bromids and iodids, with which it forms the corresponding very insoluble salts of silver. It is also incompatible with soluble carbonates and hydroxids, which precipitate the oxid of silver, and with all organic drugs and reducing agents.
Action and Uses : Silver nitrate is an antiseptic and germicide, destroying many micro-organisms in solutions of a strength of 1 : 1,000 and preventing their growth in a strength of 1 : 10,000. Weak solutions are astringent to mucous membranes and strong solutions are caustic when applied to mucous membranes, denuded surfaces, and, in some cases, to the normal skin. When taken internally silver nitrate is believed to hinder the secretion of the gastric juice, especially when the degree of acidity is excessive.
Silver nitrate is used as a mild caustic to wounds, ulcers and exuberant granulations. It is applied as an astringent and antiseptic in catarrhal infections of the mucous membranes.
Internally it is sometimes employed as an astringent in diarrhea, but its use for this purpose is not to be recommended. It has been advised for the treatment of gastric ulcer and to reduce the gastric secretion in hyperchlorhydria. Its internal use for some time may be followed by its deposition in the skin, producing the condition known as argyria.
Dosage: As a caustic, silver nitrate is used in the form of fused silver nitrate. This should be moistened before use and should be held with forceps or in a suitable holder. Care should be taken to limit its action to the affected part.
In applications to mucous membranes the following strengths of solution in water are most suitable:
To the conjunctiva a strength of 4 per cent. may be applied in small quantity and the action stopped by addition of solution of sodium chlorid. This method of use is applicable to cases of severe conjunctivitis, especially gonorrheal.
For the prevention of gonorrheal conjunctivitis in the new-born a drop of 2 per cent, solution should be instilled into the eye as soon as practicable after delivery.
For other diseases of the conjunctiva, solutions varying in strength from 0.2 to 2 per cent, are sometimes used, but it is probable that other astringents are safer and quite as useful.
To the larynx, application is made of solutions containing from 2 to 10 per cent, of silver nitrate.
For the urethra, it is employed in the strength of from 1 :10,000 to 1 :2.000, and a solution of the strength of 1 :5,000 may be injected into the bladder. A solution of from 1 :2,000 to 1 :1,000 is used as a gastric douche in hyperchlorhydria and gastric ulcer, followed after two minutes by a solution of sodium chlorid which is thoroughly mixed with the silver solution and then washed out of the stomach.
Solutions of silver nitrate should always be made with distilled water, and the mucous membranes to which they are to be applied should receive a preliminary cleansing to remove mucus, pus, food, etc., which might interfere with its action. The action may be stopped by sodium chlorid solution.
Internally the salt may be given in pill form, preferably mixed with kaolin and massed with petrolatum. The average dose is 0.01 gm. or 1/5 grain. This dose may also be given in solution when the direct effect on the stomach is desired. If the stomach contains acid it would be converted into silver chlorid; hence it should be given on an empty stomach.