Strychnin: This is a valuable stimulator and heart tonic when properly used. It promotes muscular activity of the heart much as it promotes all muscular activities. It awakens nervous stimuli and nervous transmissions to normal in all sluggish nerve functions. If for these reasons the heart acts more perfectly, and the nutrition of the heart muscle improves, it acts as a cardiac tonic. Many times, by improving the action of the heart, and also by the action of the drug on the vasomotor center, the pressure in the peripheral circulation may be increased. On the other hand, strychnin in the low blood pressure of serious illness, such as pneumonia, by no means always raises the blood pressure.
It should not be forgotten that strychnin is a general nervous stimulant, especially of the spinal cord. If it makes a nervous patient more nervous, or a quiet patient restless and irritable, it is acting for harm and should be stopped, just as caffein under the same conditions should be stopped. Strychnin may cause diminished secretion of the skin. This is not frequent, but it does occur. It may prevent the patient from sleeping. If such be the fact, strychnin is not acting for good in a patient who has cardiac weakness.
INDICATIONS FOR STRYCHNIN
Strychnin is a much overused drug. It is now given for almost everything and during almost every disease. It is true that the administration of strychnin is largely due to the evolution of the age in which we are now living. We have ceased to purge and bleed and sweat, and to give large doses of aconite or veratrum viride; have ceased to starve the patient too long; we have ceased to load him with alcohol to the point of circulatory prostration, and we have recognized that he must be braced from start to finish; strychnin is the drug which has been used for this purpose, and, as stated above, overused. Strychnin given too frequently or in too large doses for a laboring heart can prevent its proper rest; the diastole is shortened and the relaxation of the heart is incomplete, its nutrition suffers, or even irregular and fibrillary contractions of a weak heart may apparently be caused. While a large dose of strychnin, even to one-twentieth grain hypodermically, may be used once in serious emergency when it is deemed the drug to use, a dose larger than one-thirtieth grain hypodermically is rarely indicated, the frequency of such a dose should seldom be more than once in six hours, and a smaller close of strychnin may act more satisfactorily.
Strychnin is indicated when the heart is acting sluggishly and the contractions seem incomplete, and when digitalis either is not indicated or is not acting perfectly. Small doses of strychnin may aid such a heart during the administration of digitalis. In many instances in which digitalis is contraindicated, strychnin is of marked value. This is typically true in fatty hearts, and may be true in arteriosclerosis, in which it often does not increase the blood pressure at all.
2. Cardiac Stimulants.—A cardiac stimulant is a drug which makes the heart beat more strongly and the frequence more nearly normal. The drugs named as cardiac stimulants, however, camphor, alcohol and ammonia, do not leave a heart better than they found it—they are not cardiac tonics.
Camphor: This is one of the best cardiac stimulants that we possess. It is a quickly acting nervous and circulatory stimulant, acting principally on the cerebrum and causing a dilation of the peripheral blood vessels. No subsequent weakness follows after a dose of camphor. Too much will make a patient wakeful, a little often quiets nervous irritability. It should be used as a cardiac stimulant during serious illness more frequently than it has been; and during the endeavor to make a noncompensating heart again compensatory camphor will often act for good. The dose is 2 teaspoonfuls of the camphor-water every three or four hours, as deemed advisable. Each teaspoonful represents a little more than one-fourth grain of camphor. The spirits of camphor, of course, may be used, if preferred.
For cardiac emergencies, ampules of sterile saturated solutions in oil are now obtainable and are valuable. Such hypodermic stimulation acts quickly, and may be repeated every half hour for several times, if the patient does not respond. The solution should be injected slowly, and as a rule intramuscularly.
Many times while other measures are being used to repair a broken compensation, camphor makes a splendid circulatory and nervous bracer. Camphor has long been used as a so-called antispasmodic in hysteric or other nervously irritable persons. It really acts as a stimulant to the highest centers of the brain, promoting more or less nervous control. Perhaps its ability to increase the peripheral circulation may be one of the reasons that it seems at times to be almost a nervous sedative by relieving internal congestion. As just stated, after the camphor action is over there is no depression. This is not true of alcohol.
Alcohol: It is of course now generally understood that alcohol is not a cardiac stimulant in the sense of its being more than momentarily helpful to a weak heart. If alcohol is pushed when a heart is in trouble, the secondary vasodilatation and more or less nerve prostration and muscle debility will cause greater circulatory weakness than before it was administered.