Strychnine: A Potent Killer
Strychnine is one of the most potent poisons known to man and so why would you use it as a medicine? Even half a grain can kill somebody when administered two or three times a day for just several days. If larger doses are ingested, death can occur between fifteen and ninety minutes later. There are pages and pages on the Internet relating to the toxic effects of strychnine, but if you search for its medicinal properties, there is almost nothing to be found.
The question has puzzled me for several years as I know that during the Victorian era it was used therapeutically. The first time I came across it was on a document relating to my great, great, grandmother. It showed that she was treated with liquid strychnia during a spell in a mental asylum. Subsequent to that I was browsing the internet and found the attached photograph showing a bottle of chocolate covered strychnine tablets. They were clearly intended for medicinal use although the indication is not given.
In an attempt to finally understand why my great, great grandmother received such a toxic substance I undertook some thorough research. This is what I found:
Causes Death by Suffocation
Strychnine is a neurostimulant / neurotoxin that binds to glycine and acetylcholine receptors on nerve cells making them more sensitive to muscle stimulation. This allows action potentials (nerve impulses) to be stimulated with lower levels of neurotransmitters than would occur naturally. It primarily affects the nerves in the spinal cord responsible for muscle contraction, leading to involuntary muscle contractions. The effective dose of strychnine is so low, that almost any exposure is excessive. Death occurs as the muscles of the respiratory system contract and cause asphyxiation (suffocation).
It Starts with Feelings of Stiffness
Strychnine is from the bean of St. Ignatius, and has similar properties to the bean of the tree nux vomica. They both contain the alkaloid strychnine. The bean of nux vomica contains much lower levels of the alkaloid and has been studied to a greater extent. Small doses of nux vomica have been used to make up a bitter tonic. It was said to be sufficient to affect the system, with an unusual influence on the nervous system. At low doses, the tonic was found to increase appetite, speed digestion and increase urinary output. Higher doses caused irritation to the stomach causing loss of appetite, stomach-ache, pain around the heart, and sometimes vomiting or diarrhoea.
At higher doses still, it causes a general feeling of stiffness. This may be stricture in the muscles of the jaw or at the back of the neck. It may also manifest as feelings of weight or weakness with trembling of the limbs. It can be difficult to open the mouth widely and deep breathing becomes difficult. There is also an increased sensitivity to touch such that a slight tap of the skin will produce sudden and involuntary movements of the muscles. After several days administration, there is often a feeling of tickling, tingling, or itching on different parts of the skin. This can become more frequent and severe leading to shivering with darting sensations like electric shocks.
As the muscular stiffness increases the patient complains not only of rigidity of the limbs, but also of tightness about his throat, difficulty swallowing, stricture of the chest and abdomen, and even involuntary erections of the penis. As the dose increases, the spasms become more frequent, extensive and severe. They are characterised by muscle rigidity affecting the whole body. The attacks come on suddenly, like electric shocks, last usually from fifteen seconds to two or three minutes. After an interval seldom exceeding ten minutes they can recur with increased violence. As the respiratory muscles become involved, they are likely to result in death unless the patient receives intervention.
Strychnine the Medicine
Despite the dangerous nature of the drug, reports of its therapeutic value have been described. Medicinal uses appear to be linked with its ability to induce muscle contraction:
- Paralysis: The most common use appears to be in patients with paralysed or palsied limbs. The strychnine was mixed with a tiny quantity of dilute sulphuric acid and up to fifty parts glycerin before being rubbed over the limb(s) or down the spinal cord. This would heighten the sensitivity of the nerves to stimulation.
- Visual Disturbances: In its liquid form, strychnine was used as eye drops to produce contraction of the pupil and induce muscle accommodation. In patients with loss of vision, it was injected directly into the eye to induce muscle contraction.
- There is a record to suggest that strychnine could be used in patients with irritable nervous systems. Few details are given although it suggested that the starting dose should be one twenty-fourth of a grain. This could be increased to one-sixteenth or one-twelfth of a grain until the desirable effects were observed.
- Other: Mention has been made of it being used in patients with rectal prolapse (as an injection). This was presumably to hold the rectum in place and prevent protrusion.
The best form of administration was as a pill. If this had no effect an alternative form of administration was to make it into a solution. If patients were able to tolerate the bitterness, it could be dissolved in water containing enough acetic, diluted sulphuric, or muriatic acid, to produce a clear liquid. Incredibly, it could also be dosed to children, where it was suggested it be made up with a teaspoon of syrup.
The pharmacopeia’s of the time carried a warning to say that strychnine should be prescribed and administered with the greatest caution. Indeed, many instances of death are on record as a result of careless dispensing or administration.
Strychnine for Mental Health
Although I found no direct evidence for the use of strychnine in depression (other than for use in patients with irritable nervous systems above), I know my great, great grandmother was being treated for depression. I have details of her case notes that show she exhibited symptoms such as moving aimlessly, restlessness, her hands constantly twitching, slow or non-existent speech and when she did speak it was in barely a whisper. She also suffered from loss of appetite and on occasions, appeared in an atonic state (no muscle strength or tone).
I’m not an expert of depression, but I believe that psychomotor agitation / retardation is a central feature of the illness. This is particularly true in bipolar disease. The term psychomotor relates to the mental processes associated with movement or muscular activity. Symptoms of psychomotor retardation include a slowing-down of thought and a reduction of physical movements, while psychomotor agitation is a series of unintentional and purposeless motions that stem from mental tension and anxiety. Both of these apply to the symptoms displayed by my great, great grandmother.
As we’ve seen, strychnine stimulates the motor neurons and so I wonder if liquid strychnine was used to treat the psychomotor retardation that would have caused her slowness of speech, loss of appetite, loss of muscle strength and general listlessness? If it was, it seems a very drastic measure by today’s standards. In the 19th century, however, with very few effective treatments for depression, physicians presumably thought the ends justified the means. My great, great grandmother did recover from this depressive episode, and so maybe there was something to it after all.