Yohimbe. Corynanthe yohimbe.

Botanical name: 

Part Employed—The bark of the yohimbeye tree.

Spiegel obtained an extract of the bark, which contained a pigment that forms, on standing in alkaline solution, two alkaloids, yohimbin and an amorphous substance. The former crystallizes in white needles with silky lustre, and is soluble to the extent of two per cent in water, and dissolves also in alcohol and chloroform.

The agent may be given in infusion, in the form of a powdered extract, or the alkaloid yohimbin. A liquid extract is also prepared. The dose is from .001 gm. to .015 gm, of the alkaloid—from the 1/60 to the 1/4 of a grain.

Physiological Action—The action of this agent seems to be exercised directly upon the sexual centers of the spinal cord, increasing tonicity and reducing excitability.

Oberwarth and Lowy made physiological experiments on animals with the alkaloid. After injections of 0.005 to 0.015 gm. in rabbits they observed a swelling of the testicles and epididymis and their descent into the inguinal canal. In dogs and cats the swelling affects rather the penis and may go so far as to cause painful erections.

The hydrochlorate of yohimbin is a local anesthetic, of considerable value. Used in a two per cent solution it benumbs the mucous membranes in two minutes. In five minutes they are markedly anesthetic, and in ten minutes the maximum degree of anesthesia is obtained. The anesthesia lasts from one-half to three-quarters of an hour and sensation is completely restored in an hour and a half. It does not act upon the skin when applied. It must be injected.

Therapy—The current therapeutic journals of Austria and Germany have contained articles on the action of this remedy for the relief of impaired sexual function. Spiegel has made some important observations on its action. It has long been used in the form of a decoction by the natives, to increase sexual appetite. Impotence of functional origin seems to be directly influenced by it. Silberstein of Vienna says that in so-called hypochondriacal impotence, due to morbid stimulation of the inhibitory paths, as well as that produced by diminished excitability of the sexual centers, the agent is successful. Patients so afflicted become violent, and may be driven to desperation. In cases where there is a sudden failure of power, producing despondency, foreboding and general mental depression, in young married men, it is satisfactory. The knowledge of weakness has an inhibitory effect upon the exercise of the normal functional action of the organs in every field of their operation.

Impotence from onanism, or persistent nocturnal emissions, with loss of appetite, was cured by this remedy in a short time Several other cases of a similar character were experimented on satisfactorily. In cases where the same weakness was present with chronic alcoholism, resulting in chronic disease of the stomach and enlargement of the liver, the agent had a satisfactory influence. Another case was cured, who, from sexual neurasthenia, had persistent headaches.

It has been useful in operations upon the eye, nose and throat. A one per cent solution injected is non-toxic. A writer in the Standard says that if a two per cent solution be dropped into the conjunctival cul-de-sac, from five to six times in fifteen minutes, it will produce both corneal and conjunctival anesthesia. The corneal anesthesia is more pronounced and lasts much longer than the conjunctival. The eye becomes immediately suffused and continues red for more than an hour after the last instillation. There is moderate but marked dilatation of the pupil, which will last from fifteen to twenty minutes. It will be found valuable in cataract extractions and iridectomy. It has also been found useful in the removal of the nasal turbinals, and granulations, and of polypi, from the post-nasal surfaces or from the ear.

Its great advantage is in its non-toxic properties, and that it does not cause the tissues to contract. The hyperemia it induces, however, is a disadvantage in some cases. It does not keep well and there is some danger of hemorrhage after an operation.

We should confirm or disapprove the observations that have been made of this remedy. If confirmed, the agent will be a valuable addition to our resources.

The American Materia Medica, Therapeutics and Pharmacognosy, 1919, was written by Finley Ellingwood, M.D.
It was scanned by Michael Moore for the Southwest School of Botanical Medicine.