1. CARDIAC TONICS.-Digitalis: There is no drug that can take the
place of digitalis in loss of compensation in chronic valvular
disease. It acts specifically for good, and it has its greatest
success in the valvular lesions that cause enlargement of the left
ventricle, on which it acts the most intensely. It also acts for
good on the right ventricle. It has but little action on the
auricles. This is simply a question of muscle; the part that has the
greatest amount of muscle will receive the greatest benefit from
digitalis, and the parts that have the least, the least benefit. The
heart muscle is somewhat similar to other muscles; when we attempt
athletic improvement in any muscle of the body, we "train" by
stimulating it moderately at first, and are careful not to overwork
it; the object, then, is to train the heart muscle. For this reason
large doses of digitalis should ordinarily not be given to
overstimulate suddenly an overworked and weak heart. While in some
instances it has been declared that digitalis should be rapidly
pushed to the full extent and then dropped for a time, careful
experience shows that this method is often not tolerated, sometimes
does positive harm, and has at times seemed to hasten death.
Another valuable activity of digitalis is in slowing the heart by
action on the pneumogastric nerves. A dilated heart has lost more or
less of its regulating mechanism; this is the cause of its
irregularity and its increased rapidity. The action of digitalis in
slowing the heart, giving it a longer rest, and preventing it from
acting irregularly is of great value. This prolonged rest or
diastole of the heart allows the circulation in the coronary
arteries to become normal, and the nutrition and muscle tone of the
heart improves. Digitalis also increases the blood pressure, not
only by improving the activity of the heart, but also by causing
some contraction of the arterioles. This feature of digitalis action
in arteriosclerosis renders its use sometimes a question of careful
decision. The dose of digitalis under such a condition should not be
large. It may be indicated, however, and may do a great deal of
good, and it does not always increase the blood pressure.
If the patient is sufficiently ill to require the best action of
digitalis, an active preparation should be obtained. It was long
supposed that the infusion presented activities which could not be
furnished by the tincture of digitalis. This seems not to be true.
The greater value of the infusion is generally because it is freshly
made and active; the tincture which had been used previously in a
given case was old and useless; furthermore, most physicians give a
larger dose of the infusion than they ever do of the tincture. Owing
to the uncertainty of the value of the digitalis leaves found in the
various drug shops, however, and to variations in the preparation of
the infusion, it is generally better to use a tincture of known
character. The beginning dose of such a tincture should generally
not be more than 5 drops, and it should not be repeated more
frequently than once in eight hours. It is generally advisable, in
two or three days, to increase this dose to 10 drops once in twelve
hours, later perhaps to 15 drops twice a day, and still later to 20
drops once a day. This amount may then be decreased gradually, if
the action is satisfactory. Enough should be given to procure
results, and then the dose should be brought down to what seems
sufficient and best, administered once a day. The frequence advised
in the administration of this drug is because it is eliminated
slowly. Its greatest action develops a number of hours after it has
been taken, and then the action lasts for many hours; the
administration of digitalis once in twenty-four hours is perfectly
satisfactory for many patients, and more satisfactory than any more
frequent administration. On the other hand, some patients do better
on a smaller dose once in twelve hours. This frequence is always
sufficient.
Digipuratum and digitol, a fat-free tincture, proprietary
preparations accepted by the Council on Pharmacy and Chemistry for
inclusion in N. N. R., may be employed. They are standardized
preparations and may thus be more satisfactory than some
pharmacopeial preparations of digitalis, although their claims to
lessened emetic action are not borne out by recent experiments of
Hatcher and Eggleston.
Digipuratum may be obtained in tubes of twelve tablets. The advice
has been given for patients with loss of compensation to receive
four tablets the first day, three the second, three the third, and
two the fourth day. This, however, is generally an overdosage. The
most that should generally be given is one of these tablets in
twelve hours. Digipuratum fluid is also a valuable preparation.
Digitol is a fat-free tincture of digitalis which is physiologically
standardized and which bears on each package the date of
manufacture. The close is from 0.3 to 1 c.c. (5 to 15 mimims).
Digitalinum, one of the active principles of digitalis, is not very
satisfactory. It may be given hypodermically, but often causes
irritation, and the proper dose and its value are apt to be
uncertain.
Digitoxin, another active principle of digitalis, has been declared
by some investigators to be harmful, also to be liable to cause
serious disturbance of a damaged heart. Other investigators have
stated that it acts for good. Digitoxin does not represent the whole
value of digitalis, and in broken compensation digitalis itself, or
some preparation embodying the majority of its activities, should be
given. Digitoxin, however, is often valuable in conditions of
cardiac debility or slight weakening in patients who do not have
dilated hearts or edemas. The most satisfactory dose of digalen is
from 5 to 10 drops once or twice in twenty-four hours.
Digitalis should not be used when there is fatty degeneration of the
heart; it should ordinarily not be used when there is
arteriosclerosis, and very rarely, if ever, when it is decided that
there is coronary disease. Whether digitalis should be used when
there is considered to be much myocardial degeneration is a question
for individualization. One can never be sure that the heart muscle
is so thoroughly degenerated that no part of it would be benefited
by digitalis when compensation is lost; therefore, many times,
especially if other drugs have failed, small doses of digitalis
should be tried, to see if the heart will respond. Large doses or
frequent doses would be contraindicated.
The signs of overaction of digitalis are nausea, vomiting, a
diminished amount of urine, a tight, band-like feeling around the
head, perhaps occipital headache and coldness of the hands and feet,
or frequently of one extremity only, combined with a feeling of
numbness. The pulse is generally reduced to sixty or less a minute.
Such symptoms require that digitalis be immediately stopped. They
are the primary signs of cumulative action.
While many patients with ordinary dosage of digitalis may take the
drug for months and years without ever showing cumulative action,
other patients show this effect quickly. They are apt to be those in
whom the kidneys are not perfect. The signs of such undesired action
may develop slowly, as suggested by the symptoms just enumerated, or
they may develop suddenly. The pulse becomes rapid and irregular,
the heart action weak, there is severe backache in the region of the
kidneys, a greatly diminished amount of urine, or even partial
suppression, severe headache, vomiting, cold extremities and
shiverings.
The treatment of such an undesired behavior of digitalis is, of
course, to stop the drug immediately, give saline laxatives, hot
sponging or hot baths, nitroglycerin and perhaps alcohol.
Strophanthus: Strophanthus cannot be compared with digitalis, except
when the glucosid, strophanthin, is administered subcutaneously or
intravenously. Strophanthus is given either in the form of the
tincture, or as strophanthin. It has been shown that in neither of
these forms, when the drug is administered by the stomach, is the
muscle of the heart or the blood vessels much acted on. Compensation
could not be restored by strophanthus. In emergencies of serious
cardiac failure, strophanthin intravenously has been shown
apparently to save life. It acts quickly, and its power of
stimulating the heart and contracting the blood vessels lasts for
many hours. It is rarely, however, that the dose should be repeated,
and then not for twenty-four hours, but during that twenty-four
hours the patient may be saved until other drugs which act more
slowly have been absorbed, or perhaps until the emergency has
passed. It probably should not be given if the patient has
previously had good dosage of digitalis.
There are many, however, who believe that they obtain considerable
value from the tincture of strophanthus, and there seems to be no
doubt that although strophanthus, given in the form of the tincture
and by the mouth, may not increase the muscle power of the heart, it
many times acts as a satisfactory cardiac sedative. Under its action
the patient becomes less nervous, the heart often acts more
regularly, and the low blood pressure may improve. We should not be
quite ready to discard the internal use of the tincture of
strophanthus.
The tincture of strophanthus readily deteriorates, and the
preparation ordered should be known to be a good one.
Caffein: This should not be given or allowed, even in the form of
tea or coffee, to patients who have valvular lesions with perfect
compensation, as it is a nervous and cardiac stimulant and may cause
a heart to become irritable. It raises the blood pressure slightly,
acts as a diuretic, and hence is often of great value when used
medicinally. It should be ranked as a stimulotonic to the heart. It
increases its activity, but gives it a little more strength. It will
rarely slow a rapid heart; it will often stimulate a sluggish, slow
heart; it may increase the irritability of an irritable heart. As it
is a cerebral stimulant, it should not be given late in the
afternoon or evening, as it may prevent sleep.
The most frequent form of caffein used is the citrated caffein. The
dose is 0.1 gm. (1 1/2 grains) two or three times in the early part
of the day, or 0.2 gm. (3 grains) once or twice during the morning.
A few much larger doses may be given if desired. A cup of coffee may
be given the patient medicinally: as a substitute for the drug, an
ordinary cup of strong coffee containing between 2 and 3 grains.
Other preparations of caffein may be selected if desired, or a
soluble preparation may be given hypodermically.
Caffein is indicated if digitalis is contraindicated or does not act
satisfactorily, and the patient is not nervously excited, but
perhaps is stupid or apathetic, and also when diuresis is desired.
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.