Prepared by percolation of powdered cantharides, 100 parts, with alcohol
to make 1000 parts.
DOSE.--Horses and cattle, 2 to 4 dr.; sheep and pigs, 15 to 30 m.; dogs,
2 to 15 m.
ACTIONS.--Externally, is rubefacient, irritant, vesicant, according to
the strength used, it promotes water blister; counter-irritant, etc.
Cantharides acts more powerfully on the skin of horses and dogs than on
that of cattle and swine. If applied over an extensive surface,
absorption and poisoning may occur.
Internally cantharides is an irritant, and produces its effects on any
part which the free cantharidin is brought into contact. When swallowed
it irritates the digestive mucous membrane; large doses produce
gastro-enteritis. The active cantharidin is absorbed, and in the blood
forms a non-irritant albuminoid, but in the kidneys is again liberated,
developing its characteristic irritation, medical doses stimulating the
urino-genital tract, causing diuresis, and in some animals increases
sexual appetite; full doses induce inflammation, slow and painful
discharge of bloody urine.
USES.--Externally cantharides is employed as a blister rubefacient or as
a counter-irritant; blisters are formed in from two to eight hours. If
repeatedly used it may cause sloughing of the tissue; cantharides may be
used wherever a blister or counter-irritant is required, except in
inflammation of the urinary organs, as it is absorbed and will increase
the inflammation. Cantharides conjoined with red mercurous iodide and
adeps is usually employed in the treatment of diseases of the bones,
joints, bursae, ligaments and tendons. In exostoses, as bone spavin and
ring bone, used most effectively after the actual cautery, to secure
absorption and resolution, or anchylosis. Always clip off the hair close
before applying a blister, tie or muzzle the animal so he cannot bite
it; leave blister on forty-eight hours, then wash and grease the parts
daily. A cantharides blister is sometimes beneficial in hastening the
formation of abscess (distemper); also to stimulate indolent ulcers or
wounds; it causes swelling and closes the opening of small umbilical
hernias of foals and calves. It is also valuable in closing and sealing
punctured wounds into joints and synovial cavities. The tincture of
cantharides can be applied once or twice daily, full strength, when the
exudation of much serum is desired. Cantharides is seldom used
internally except in incontinuence of urine from debility or partial
paralysis of the bladder. Seldom used to increase sexual desire. The
tincture of cantharides should be employed when the drug is administered
internally.