Potassii Cyanidum

Cyanide of Potassium

Cyanide of Potassium. In white, opaque, amorphous pieces, having a sharp, somewhat alkaline and bitter-almond taste, and an alkaline reaction. It is deliquescent in moist air, readily soluble in water when reduced to powder, and sparingly soluble in alcohol. Dose, gr. 1/10—gr. 1/6.

Antagonists and Incompatibles

Acids decompose it and set free hydrocyanic acid. As respects its physiological properties, its antagonists are the same as those of hydrocyanic acid.

Synergists

Same as for hydrocyanic acid.

Physiological Actions

The effects of this salt have been already mentioned in sufficient detail in the preceding article, so far as they correspond to hydrocyanic acid. It has, however, some special physical properties which separate it slightly from the powerful agent which enters into its composition.

Applied to the unbroken epidermis, the cyanide of potassium produces at first a sensation of coldness, followed by tingling and itching, and in a half-hour the skin is found to be somewhat reddened. Prolonged contact produces a phlyctenular or eczematous eruption.

Systemic effects are produced by the local and external use of the cyanide of potassium, viz., slowing of the pulse and respiration, muscular weakness, drowsiness, and coldness. Lethal effects may follow prolonged contact with the skin, even when the epidermis is unbroken. Applied to a wound or abraded surface, this salt causes a burning pain, excites a high degree of inflammation, and produces prompt lethal effects.

Therapy

Cyanide of potassium may be prescribed as a substitute for hydrocyanic acid in all of the maladies for which the latter is used. This salt has, however, some special applications which we owe to Trousseau. This eminent observer has shown that a solution of the cyanide applied to the seat of painful sensations gives great relief in various forms of reflex headache, gastric, cardiac, pulmonary, and menstrual. The headache which accompanies the pyretic state is, according to the same authority, cured or greatly alleviated by the cyanide solution, while at the same time a favorable influence is exerted over the temperature. Rx Potassii cyanidi, gr. x—Эj; aquae lauro-cerasi, oz iv. M. Sig.: A compress, moistened with the solution, to be applied to the seat of pain. From a quarter to a half hour of contact with the skin usually suffices.

A solution of the cyanide of potassium, of the strength given above, will remove the stains of nitrate of silver, and also the dissecting-room odor, from the hands.

Cyanide of potassium, in the form of ointment or solution, is an excellent remedy for allaying irritation in various cutaneous diseases. In pruritus and urticaria, the following formula (McCall Anderson) gives relief: Rx Potassii cyanidi, gr. vj; pulv. cocci, gr. j; ung. aq. rosae, oz j. M. Sig.: Ointment. In eczema with pruritus, the same authority recommends the following: Rx Potassii cyanidi, gr. v; sulphuris, potassii bicarb., āā 3 ss; pulv. cocci, gr. vj; axungiae, oz j. M. Sig.: Ointment. A solution of the cyanide of potassium is one of the most effective applications for that very troublesome disorder, pruritus pu-dendi. Rx Potassii cyanidi, gr. xv; aquae lauro-cerasi, oz viij. M. Sig.: Lotion. This formula is also serviceable in lichen and prurigo (Hardy).

Entomologists make use of the cyanide to destroy insects without injuring their structures. One part of the cyanide, two parts of plaster of Paris, and one and a half part of water, made into a paste and poured into a wide-mouthed bottle, sets into a solid mass, which gives off the vapor of hydrocyanic acid (Squire).

Authorities referred to:

Trousseau et Pidoux. Traité de Thérapeutique, etc., vol. ii, p. 265, et seq. Trousseau, A. Clinique Médicale, vol. ii, p. 332.