The
Foxglove Foxtrot.
Ivor Hughes
Digitalis
or the Foxglove as it is more commonly known has proved to be a most useful
if not unpredictable plant drug. It was popularised and then adopted by the
global medical profession by a one Dr William Withering.
Medical legend
tells us that he obtained the knowledge of 'Foxglove' .. and this quite by
chance .. from a Shropshire Peasant Woman. William Withering had gained his
clinical experience by human experiments at a free clinic for the poor in
Birmingham England. This made him, outside of London, the richest Doctor in
the realm.
The man who made the Dutch town of Leiden the greatest medical center in
Europe at that time, was to led protest against the medical establishment as
follows;
"When
one compares the good which a half dozen true sons of Aesculapius have done,
since the beginning of the healing arts on this earth, with the evil which
the vast numbers of doctors in this profession have caused to mankind one
will doubtless consider it would have been far better if there had never
been physicians on this earth."
Herman Boerhaave 1668-1738
Then further ..
"Selectivity
is never absolute, even a highly selective drug is likely to react with some
structure other than the one for which it has been designed. Absolute lack
of toxicity is an impossibility because absolute selectivity is a chemical
impossibility"
Professor Rene Dubos, Microbiologist
The
Scientist Roger Williams, has presented evidence that biological
idiosyncrasy can vary from person to person by factors of 20 or more within
a racial group, so how much more is it complicated by the biological
idiosyncrasy between races? Perhaps Chinese herbs elicit a better
pharmacological response from an Asiatic, than they do from a Caucasian?
The route of administration of a medicinal herb, has a direct bearing on how
much of its constituents are taken up by the body. Moreover the route of
administration has a profound effect on how those constituents will behave
in an individual. The herbalists used foxglove as an ointment. Now this is
an extremely important point. Because the herbalists had already solved the
problem which Science and Medicine has still failed to solve after 250
years. In fact as we shall see, with their use of the isolated constituents
and incorrect method of administration, they have caused problems where
hitherto there were none. However credit where it is due, they have made a
lot of money, in spite of all the bodies that have had to be swept under the
carpet.
To hammer out the point let us return to the anvil, the Foxglove, (Digitalis
purpurea L.). The medicinal properties of the foxglove has been known since
at least the 10th century, and was most certainly used by the Physicians of
Myddfai for dropsical complaints (water retention). Those Celtic physicians
were also advocates of the single herb.
Medical history would have it that an English doctor, William Withering
(1741 - 1799), unlocked the secrets of the Foxglove. Dr. Withering obtained
his degree in medicine from Edinburgh University at a time when plant drugs
were held at arms length by institutionalized medicine.
However, Dr Withering's disdain for 'folk medicine', was tempered by his
love for a young botanic artist called Helena Cooke, who was numbered among
his first patients, and who he was destined to marry. Withering gained his
clinical experience with digitalis at a free clinic for the poor in
Birmingham, England, and the rest as they say is history.
From the standpoint of Herbal Pharmacy, Dr Withering made two major
contributions; firstly, he slowed the gallop of the iatro-chemists and
forced a re-examination of what folk medicine had to offer. Perhaps more
importantly, he established for digitalis, what is nowadays called a
therapeutic index.
A therapeutic index is a type of scale that sets a lethal dose and an
effective dose, with a therapeutic dose being a ratio of the lethal (LD) and
the Effective (ED). All drugs have a unique therapeutic index. This is a
fact recognised by all herbalists although the application is through
combined experience and intuition of the powers of the herb.
Withering was not entirely successful, and neither is modern medicine, for
the common sense reason that on one side, there is the biological
idiosyncrasy of the plant drug, and on the other the biological idiosyncrasy
of the individual. Nature has solved that problem very nicely; a toxic dose
is not necessarily a lethal dose and the onset of toxicity produces vomiting
and purging as the body evacuates the offending substance.
Digitalis entered regular medical practice in 1755; because of its value, it
quickly bridged the English Channel and was embraced by medical men
throughout Europe. After a shaky start it established itself in the European
Pharmacopeias. Apart from D. purpurea, other members of the family
Scrophulariaceae were also admitted, e.g., D. ferrugine, D. ambigua, D.
grandiflora and D. lanata. D. lanata contains a group of glycosides that
have been called lanatosides A, B, C, D, and E, which are used by the
pharmaceutical industry to manufacture the secondary glycosides, digitoxin,
diginatin, dioxin, gitaloxin and digoxin. This is done by the removal of one
acetyl group and one glucose molecule (See Section 8-21). (The lethal
synthetics again ! which are optically inactive)
The preparation introduced by Withering was Digitalis leaf, and because of
the natural variations from batch to batch, and the amateurish prescribing
of Digitalis, gastric upsets (vomiting and purging) were common place. In a
bid to circumvent these problems, various preparations were placed on the
market. Because of the importance of the Digitalis spp., they have undergone
intense scientific scrutiny, but even today, over 200 years later, the only
reliable test of potency is Biological assay (Section 9-76), which would
seem to indicate that the potency or otherwise of a batch, is not determined
by a single, or even 2 or 3 glycosides and saponins, but rather, that it is
determined by the synergistic complex of the plant itself.
In the late 1800's, with improved methods of transport and the increasing
mobility of people across national borders, coupled with the medicalisation
of society, it became evident that standardized formulae for potent drugs
was, of necessity, desirable. In 1902, the first international conference
was held in Brussels, resulting in an International Agreement of unified
formulae for potent drugs and their respective preparations.
Over the years, further conferences were held under the auspices of the
League of Nations. That was succeeded by the World Health Organization, who
in May 1950, at the third global assembly, approved the publication of the
first volume of the International Pharmacopoeia. The IP is not a legal
standard in any nation, unless it is first adopted by the relevant authority
of that nation.
Withering's preparation of Digitalis leaf is rarely prescribed today, one
would suspect because of lack of clinical experience, but when it is, then
Prepared Digitalis (Digitalis pulverata) is dispensed. Prepared Digitalis is
a coarse powder (18 mesh/Table 6-45A), that has been biologically assayed
and adjusted to contain a specific number of units of activity. It should be
understood that units of activity do not have a specific weight or volume,
but are related to a specific physiologic function, and will vary from drug
to drug; in the case of digitalis, it is related to heart function (see
9-76, Biological Assay).
The British Pharmacopoeia, 1958, states that Prepared Digitalis must contain
10 units in one gram (10IU/gm), and that over-strength preparations may be
adjusted by the addition of under-strength digitalis, or powdered grass or
lucern. The latter two substances are considered to be medically inert.
The reference sample of the digitalis was not tampered with, its activity
was simply noted 'in vivo' (in life). Subsequent preparations
were measured against it by further biological assay, and then an arbitrary
standardization procedure (Section 9-5) was adopted. The preparation meets
the criteria required by herbal pharmacy, in that the blend effect, or its
synergy, remains intact. All that is now needed, is the clinical skill to
balance the drug against the aptly named patient.
The therapeutic dose of digitalis is said to be 60% of the toxic level, but
which 60% are we specifying ? The patients biological idiosyncrasy is not a
fixed point, that once determined remains a constant, the dynamic
equilibrium of the individual not only varies from season to season, but
from hour to hour. That which is a therapeutic dose of Digitalis at 4pm, may
prove to be a toxic dose at 4am. Therapeutic in spring, may be toxic in
winter; and of course, it is indisputable fact that the same problems are
mirrored in the plant. If only people could be standardized as well !
Orthodox medicine, and all those branches of science attendant on it, seek
to reduce the variables to a constant, and so it was, to the active
constituent and synthetic analogues. We will recall that one of the
traditional uses for the foxglove, was in the treatment of dropsical
complaints. Its stimulating effect upon the kidneys, would appear to be via
the renal artery and by association, the stimulation of the heart.
When isolated heart glycosides, natural or synthetic, are administered to
the individual, they not only stimulate the heart muscles, but they also
have an effect on the adrenal cortex, which secretes the hormone
aldosterone, which is a response to reduce cardiac output, and/or reduce
blood volume.
The increased aldosterone produces an increased reabsorption of sodium via
the renal (kidney) tubule. The sodium (Na -) imbalance produces
hypertension, which the body tries to correct by reabsorbing water which was
to be voided by urination. Tissues become bloated with water, and further
strain is placed on the kidneys and the heart, which may also provoke
Potassium (K+) retention. Na and K are ionic species (see Section 8-6 and
8-36 through 8-39), consequently, the electrolytic and acid/base equilibrium
of the body is disturbed.
To combat this, a synthetic diuretic, usually of the thiazaide or
mercuric type, is then administered. For an elderly or debilitated patient,
the onset of urination is sudden and violent, thus humiliation is also added
to the burden. The synthetic diuretics tend to flush excessive amounts of
potassium from the body, and in some cases can initiate potassium retention.
Potassium imbalance has an adverse effect on numerous systems, e.g., lymph,
liver, kidneys, heart, auditory, pancreatic. Some very common side effects
are gout, diabetes and deafness. Potassium supplements, because of their
alkaline nature, can damage the lining of the stomach which will then
etc,etc ad nauseam.
When we tamper with natures synergy at any level there is a price to be
paid, not by the physician but by the patient. At our current level of
knowledge such procedures may only be justified by medical emergency, i.e.,
to save a life, but once a patient has been stabilized and there is evidence
of organic impairment which necessitates ongoing treatment then, to manage a
maintenance regime around, such procedures is insanity not medical science.
Maintenance should be managed around a natural drug and naturopathic dietary
principles.
Cardiac problems arise from malfunction of different systems of the body.
Cardiac malfunction is a symptom and digitalis is not suitable for all
conditions. Nature has provided a range of natural heart drugs.
To reiterate, the herbalist had already solved the problem. However there is
no money to be made from whole leaf ointments because the Pharmaceutical
Companies cannot patent the leaf.
Related Links
Foxglove
Monograph Digitalis
BP
Back to Tutorial
Index
Library
|