Cantharis

Cantharides

Cantharides. Cantharis vesicatoria. Cantharide, Fr.; Spanische Fliegen, Ger.

Tinctura Cantharidis

Tincture of cantharides. Dose, τη ij—τη xv.

(The other preparations of cantharides, which are used externally only, will be taken up in Part III of this work.)

Composition

The principal constituent of cantharides is a neutral, crystallizable principle, cantharidin. It contains also an oil, fatty matter, and an odorous material.

Antagonists and Incompatible

There is no chemical or physiological antagonist to cantharides. Poisoning by this substance should, therefore, be treated on general principles. The stomach should be evacuated by emetics or the stomach-pump; mucilaginous substances should be freely administered; the gastro-enteritis should be treated by opium, etc.

Synergists

Oils and fats increase the solubility and favor the absorption of cantharidin. The physiological actions of this agent are promoted by the other members of this group.

Physiological Actions

The odor of cantharides is nauseating, fetid, and peculiar. In contact for a sufficient time with the skin or mucous membrane, it excites considerable burning, inflammation, and vesication. In the stomach it causes a sensation of heat, severe gas-tralgia, nausea, and vomiting. Notwithstanding the insolubility of cantharidin, it readily diffuses into the blood. It is actively stimulating to the circulatory system, and a rise of temperature, with thirst, follows in an hour or two. Under these circumstances, the urine becomes scanty and burns the passages; severe pain is experienced in the back and loins; priapism occurs; and the urine, voided with great difficulty, frequently contains albumen and blood. To this excitement of the circulatory system and of the genital organs succeeds a condition of depression, in which the pulse falls, the arterial tension is lowered, and the temperature declines (Radecki).

When a toxic dose is swallowed, in a short time a sense of constriction of the aesophagus, with difficulty of swallowing, and ptyalism, occur. Intense gastric pain, vomiting of glairy mucus streaked with blood, intestinal pain, abdominal tenderness, tenesmus, and mucous and bloody stools, are produced. Violent irritation of the genito-uri-nary organs is also experienced, manifested by lumbar pain, strangury and bloody urine, priapism, swelling and inflammation of the external genitals. In most cases of poisoning by cantharides, cerebral effects, consisting of muscular trembling, partial or general convulsions, coma, and insensibility are produced. Abortion has been caused by toxic doses of cantharides, and after death violent metro-peritonitis, gastro-enteritis, and general peritonitis, have been observed. It is questionable whether abortion can be caused by a dose less than toxic.

Cantharides has frequently caused dangerous symptoms, when used with a view to induce venereal excitement. That it does promote the sexual appetite is probably true, but this result is accomplished only by the use of a quantity sufficient to cause vascular turgescence of the sexual organs.

Therapy

In acute desquamative nephritis, after the subsidence of the acuter symptoms, good results are obtained from cantharides. The local condition in which this remedy is serviceable consists in hyperaemia with loss of vascular tonus. Chronic pyelitis and chronic catarrh of the bladder are occasionally remarkably benefited by the long-continued use of small doses of cantharides. Irritability of the bladder, more especially as it occurs in women, without the existence of acute inflammation, and not produced by uterine displacements, is sometimes quickly and entirely relieved by this remedy. The irritable state of the bladder and the vesical tenesmus, which accompany chronic prostatic disease, are also sometimes surprisingly relieved by cantharides, but the author is unable to indicate the special circumstances to which it is adapted.

Gleet and prostorrhoea are benefited by cantharides when these maladies occur in subjects of a relaxed fiber, with feeble circulation. Ringer makes the extraordinary statement that one drop of the tincture given three times a day will prevent chordee.

When spermatorrhoea actually exists, and is due to deficient tone of the seminal vesicles, the erections being feeble, and the sexual feeling torpid, good results are obtained by the use of cantharides. In cases of scanty menstruation, occurring in women of lax fiber, with cold hands and feet, improvement follows the use of this remedy. It sometimes happens that menorrhagia is due to relaxed vessels and a general lowering of the vascular tonus: under such circumstances cantharides may render important service. In these disorders of the sexual system, characterized by deficient power, the good effects of cantharides are promoted by the use of iron. The tincture of cantharides is the most eligible preparation for internal administration. In chronic affections of the genito-urinary passages the dose will range from five to fifteen drops, rarely the latter, three times a day.

Liebreich has brought forward cantharidin as a remedy for phthisis, based on the action of this agent on the capillaries whereby an abundant diffusion of blood serum takes place about pathological new formations. Now it is a well-known fact that blood serum is destructive of pathogenic micro-organisms. Hence his contention that to arrest the progress of tuberculosis it is only necessary to inject subcutane-ously an agent like cantharidin, which environs the organism and cuts it off from further extension by causing an outpouring of serum about the tubercular deposit. Cantharidin has acid properties and combines with bases to form salts. Liebreich recommends the following comination: Cantharidin (cryst.), 3 grains (0·2 grm.); potassium hydroxide (pure), 6 grains (0·4 grm.); water, 5½ drachms (20 grm.). Heat over a water bath until clear; then add, while still on the water bath, and very cautiously, cold water enough to make when cooled 1 litre (32 fluidounces). The dose should never exceed 1/100 grain of cantharidin, and the initial quantity ought not be greater than one third of that.

Good results have apparently followed this treatment, and the views of Liebreich have been supported by Frankel, Guttman, and others.

Authorities referred to:

Casper's Practisches Handbuch der gerichtlichen Medicin, by Liman, zweiter Band, p. 576.

Husemann, Dr. Theod. Handbuch, zweiter Band, p. 538 el seq.

Radecki, Fr. Die Cantharidinvergiftung. Inaug. Diss. Schmidt's Jahrbucher, voL cxxxviii, p. 17.

Ringer, Dr. Sydney. Handbook of Therapeutics.

Taylor, Dr. A. S. On Poisons, fourth edition, London, p. 524.