This section is from the book "Botanic Drugs Their Materia Medica, Pharmacology and Therapeutics", by Thomas S. Blair. Also available from Amazon: Botanic Drugs, Their Materia Medica, Pharmacology and Therapeutics.
Strychnos Nux vomica. Universally official. Ig-natia, another strychnine-bearer, is separately considered. See it for the pharmacology of brucine. There are numerous other plants bearing strychnine and brucine, but they are of no vogue in medical practice in this hemisphere.
Strychnine is powerfully antiseptic, but is too dangerous to use in this direction. Even in minute doses it manifests the properties of the bitters. See "Gentian." In small doses nux vomica is one of the best of the bitters. Lacking aromatic properties, it should be combined with other bitters.
Small doses increase intestinal peristalsis. Strychnine elevates the body temperature. A cumulative action has recently been demonstrated, the drug seeming to linger in the nervous tissues; it is eliminated slowly.
Small doses also stimulate the special senses.
Larger doses make the muscles stiff and heighten reflex excitability, external stimuli resulting in motor excitation, which may, in full dosage, result in a convulsion. The medullary gray matter is stimulated, as are the respiratory, cardiac, and vaso-motor centers.
The drug does not act strongly on the mammalian heart. Quite opposite to digitalis, strychnine does not aid in cardiac failure and auricular fibrillation, though it may be a cardiac tonic. Blood-pressure is raised, probably from the excessive muscular contractions induced by the drug.
A feeling of uneasiness and reflex irritability is followed by muscular twitching, a sense of suffocation, and characteristic convulsions. They are first clonic and then tonic, opisthotonos resulting. There are remissions, with complete muscular relaxation; increasing in intensity, the seizures affecting the facial muscles and producing the characteristic risus sardonicus. The patient remains conscious but suffers great pain, perhaps with vomiting and purging. Finally asphyxia, cyanosis, dilated pupils, coma, exhaustion, and death. Three or four seizures are usually fatal. The minimum lethal dose in an adult is 1/2 grain.
Give emetics, the best one being apomorphine hydrochloride. Wash out the stomach if the patient is seen early, adding potassium permanganate to the water. If a fatal dose has been taken, by the time the physician arrives these measures are useless; in that event keep the patient under chloroform. Keep the patient warm. Give oxygen if available. Artificial respiration may be employed.
For use in small dosage nux vomica is preferable to strychnine. These indications are as a tonic and to influence the gastroenteric tract.
As a tonic nux vomica and strychnine act on the gastric mucous membrane, excite the vasomotor and motor centers in the cord, increasing the activity of the circulation and promoting general systemic tone. As a stomachic bitter, it is well to combine tincture nux vomica with one of the fluid preparations possessed of aromatic properties. Impaired digestion, especially if the system at large is feeble, is markedly improved. Gentian, cinchona, and hydrochloric acid combine nicely with nux vomica in such cases. In anemia the tonic action is enhanced by iron.
In gastrointestinal disease it is to be noted that even minute doses stimulate peristalsis. By long continuance of such doses, torpor of the abdominal organs is somewhat overcome. Gastrointestinal fermentation is often kept up by want of tone, and fairly full doses of nux vomica do much to end the condition. In gastric catarrh not due to serious organic changes, atonic constipation, some cases of vomiting, especially that associated with infantile diarrhea, and in sea-sickness, the drug is of value in fairly full dosage.
On the circulation nux vomica and strychnine are both tonic and stimulant, especially when troublesome abdominal distention is aggravating a weak circulation.
On the heart strychnine has its action by rise of blood-pressure, not by direct stimulation of the heart muscle, as appears under the pharmacology. Next to digitalis, strychnine is the most important cardiac remedy, but it should not be used in fatty myocarditis. Failure of the heart's action nearly always indicates strychnine hypodermatically. This urgent use may be life-saving when aggravations occur in chronic cardiac disease and in bradycardia. Here, along with digitalis, it slows the heart, increasing the period of physiological rest. Congenital heart disease should be treated systematically with nux vomica or strychnine.
Strychnine is a powerful and constant stimulant to the respiratory center. In pneumonia it may be urgently demanded when death is imminent from dilatation of the right heart. Give it at frequent intervals hypodermatically in such cases. Failure of the respiration from poisoning may demand similar treatment, perhaps combined with caffeine or strong coffee. With expectorants, strychnine or nux vomica may be given if secretion is free; but dry cough contraindicates them. In the weak and shallow respiration of bronchitis and other acute respiratory disease, they serve a good purpose.
As a tonic to the general nervous system nux vomica and strychnine are unsurpassed if properly used. If there are defined central lesions or degenerative nerve-tissue changes, these agents may fail or even do harm; but hysterical, neurasthenic, diphtheritic, syphilitic, and mineral-poison paralyses may be, and often are, much benefited. If scleroses or effusions exist, avoid these drugs; you may increase blood-pressure and do infinite harm. However, after the lesions become quiescent, say in hemiplegia, then these dangers do not exist. In diphtheritic paralysis there is always a possible danger from the use of strychnine, and adrenalin may often well be used in its place. In the later manifestations of infantile paralysis strychnine has been used intramuscularly. Be careful of the drug in shock.
When the sphincters lack tone, as in nocturnal enuresis and incontinence of urine, nux vomica and strychnine often are of value. Neuralgic dysmenorrhea should be treated by giving strychnine between the menstrual periods.
Fl. nux vomica, average dose, 1 minim; extract, 1/4 grain; tr., 8 minims. Much smaller, but rarely much larger, doses may be indicated. Strychnine, average dose, 1-40 grain, rarely over 1-20 grain. The nitrate and sulphate in same dosage.
Strychnine enters into the composition of many elixirs, syrups, and pill formulae.
Brucine is separately discussed. See "Ignatia." Strychnine enters into combinations readily, such as the soluble iron and strychnine citrate (average dose, 2 grains).