Definition. - It should contain not less than 99 per cent. of pure potassium permanganate.

Origin. - Obtained by heating together caustic potash, potassium chlorate, and manganese dioxide. The potassium manganate formed is converted into the permanganate by boiling it in water.

Description and Properties. - Slender, monoclinic prisms, of a dark-purple color, almost opaque by transmitted light, and of a blue, metallic luster by reflected light; odorless, with at first a sweet and afterward a disagreeable and astringent taste; permanent in the air; soluble in 16 parts of water. In contact with alcohol it is decomposed.

Potassium permanganate should be kept in glass-stoppered bottles, protected from light, and should not be brought in contact with organic or readily oxidizable substances.

Dose. - 1/2-2 grains (0.03-0.12 Gm.), as a pill [1 grain (0.065 Gm.), U. S. P.].

Antagonists and Incompatibles. - Organic matter easily deoxidizes it, causing an explosion.

Synergists. - Other antiseptics enhance its germicidal action.

Physiological Action. - Potassium permanganate in contact with organic matter gives up a part of its oxygen. It loses its color thereby and is no longer active. Its action is very energetic but very superficial.

Therapeutics. - Externally and Locally. - In concentrated solutions or in substance it is a mild escharotic. Its readiness to part with oxygen renders it of great value as a deodorant, and in dilute solutions, 1 to 5 grains (0.06 to 0.32 Gm.) to 1 ounce (30 Cc.) of water, it is a useful application to foul ulcers, cancer of the uterus, vagina, etc. A solution of this drug is employed for various purposes as an antiseptic, germicide, and deodorant, in the treatment of gonorrhea, leucorrhea, diphtheria, putrid sore throat, ozena, nasopharyngeal catarrh, cancer of the tongue, and syphilitic ulcers.

A weak solution of potassium permanganate is an efficient application in bromidrosis, and a 1: 2000 or 1: 5000 solution is recommended in purulent ophthalmia. Potassium permanganate should not be used as an antiseptic in the peritoneal cavity, on account of its irritating properties. It is employed extensively in surgical practice for washing the hands and utensils.

Internally. - Like iron, potassium permanganate has been employed in anemia, although far inferior to the former drug. Favorable reports are given regarding its value in gastric fermentation and lithiasis.

It has been recently advocated as an antidote to morphine-poisoning. Later investigations do not support the early claims. It has an oxidizing effect and undoubtedly destroys the free morphine substances that may remain in the stomach or be eliminated there.

Administration. - For internal use potassium permanganate should always be given in pill form, kaolin being used as an excipient, lest an explosion occur.