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

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