This section is from the "A Handbook of Useful Drugs" book, by State Medical Examining and Licensing Boards.
Properties : Mercuric chlorid occurs in the form of heavy colorless crystals or a heavy white powder having an acrid and persistent metallic taste. It is permanent in the air. It is very slowly soluble in water (1:13), and freely soluble in alcohol (1:3). Ammonium chlorid, sodium chlorid, tartaric acid and citric acid enhance its solubility in water.
Incompatibilities: Mercuric chlorid is precipitated from its solutions by albumin, but redissolves in an excess of the albumin solution. Albumin in the form of egg-white forms the most useful antidote to corrosive sublimate, but a great excess should be avoided and the antidote should be followed by an emetic.
Mercuric chlorid is incompatible with soluble carbonates and hydroxids, forming insoluble mercuric oxid, and with iodids, forming mercuric iodid or complex mercuric iodids. It is incompatible with many alkaloids and other organic compounds. It is reduced to calomel or metallic mercury by iron, zinc and reducing agents in general. It dulls and tarnishes surgical instruments.
Action and Uses: Mercuric chlorid is chiefly used as a germicide and an antiseptic. It is also sometimes used as a specific antisyphilitic agent. In a proportion of 1:20.000 it kills non-spore bearing bacilli and in the proportion of 1:300,000 inhibits the growth of many bacteria. Spores of Bacillus anthracis are killed by a solution of 1:1,000. Its disinfectant action is limited by its deficient penetration and by the fact that it is greatly reduced by combination with organic matter. Mercuric chlorid is irritant to the skin, setting up a dermatitis. A sufficient amount may be absorbed from the skin to produce serious poisoning. The effects of the poison when absorbed from the skin or mucous membranes are seen in gastro-intestinal irritation, diarrhea, frequent foul-smelling and bloody passages resembling those of dysentery, various nervous symptoms, irritation of the kidneys with albumin and casts in the urine, marked weakness, etc. When taken in poisonous doses by the mouth it produces, in addition, irritation and ulceration of the mouth and throat, vomiting and corrosion of the mucosa of the stomach and intestines. Salivation and swelling and ulceration of the gums sometimes occur.
Dilute solutions of mercuric chlorid are used by hypodermic or intramuscular injection in the treatment of syphilis. The injections must be repeated daily and have the disadvantage of causing considerable pain.
Mercuric chlorid is used as a local application to the skin in some forms of skin disease, sometimes as an antiseptic, but also for the purpose of producing exfoliation of the epidermis. It is sometimes used in 1 per cent, alcoholic solution as an application to corneal ulcers. In the proportion of 1:5,000 it may be added to collyria to prevent fungus growths.
Dosage: From 0.002 to 0.01, or from 1/30 to 1/6 grain, in solution or in pill form. As an antiseptic application it may be used in solutions varying in strength from 1:20,000 to 1:2,000. For disinfection of clothing a solution of 1:1,000 may be used. To excite dermatitis and exfoliation, solutions varying in strength from 1:1,000 to 1:200 may be used, but caution should always be exercised in employing the stronger solutions for fear of absorption of the poison. The injection of mercuric chlorid solutions into the body cavities should be undertaken only with the greatest caution.