Free A is for Arsenic by Kathryn Harkup

evidence of something more sinister? There is no record of digitalis being prescribed to van Gogh, however, and the foxgloves in the doctor’s portraits may be a coincidence. The artist may just have had a strong liking for the colour yellow and the artistic effect of haloes around the stars in the sky, rather than being under the vision-warping influence of digitalis.
    Digitalis would have had no effect on van Gogh’s epilepsy, but at that time drugs that had proved effective in treating one condition were often prescribed for others, in case they provedto be a panacea for all ills. There is some scientific credibility to this way of thinking. Many drugs originally developed for a specific treatment have been found subsequently to be more effective in treating other conditions. Viagra is a classic example. This drug was originally developed to treat angina, by relaxing the coronary vessels that supply blood to the heart. The target enzyme was phosphodiesterase; this inactivates a messenger molecule 47 that causes the dilation of blood vessels, amongst other roles. The drug is effective at increasing blood flow, but it turns out that the heart is not the organ most affected. In addition to its qualities for enhancing men’s sex lives, Viagra can affect the dilation of blood vessels throughout the body; those taking heart drugs or who have low blood pressure shouldn’t use Viagra as there will still be some interaction with the heart. The drug’s effects on blood vessels in the brain can also cause headaches, but its most common side effect is a blue tint to colour perception, caused by its interaction with phosphodiesterase in the cone cells of the eyes.
    Is there an antidote?
    In an emergency case of digitalis overdose, atropine can be given, to stimulate the heart. In the case of a dose of digitalis that does not kill the patient quickly, potassium chloride (KCl) dissolved in fruit juice can be given every hour until the normal heart rhythm is restored, but the individual must be carefully monitored to avoid potassium toxicity. Complete inactivity is enforced for patients, especially ones with impaired kidney function who cannot process the potassium chloride or other drugs efficiently. The patient is kept completely still until normal heart function is restored.
    Today, more drugs are available to treat overdoses of digitalis, and the chances of surviving a huge overdose are much higher. Phenytoin can be given in cases of acute digitalis poisoning, for example, if the patient is unresponsive to potassium therapy.This drug increases the metabolism of the digitoxin in the body, rendering it ineffective more rapidly than under normal circumstances. Another drug, cholestyramine, reduces the half-life of digitalis drugs in the body. Specific digoxin antibodies are also now available to inactivate the drug in the body.
    Some real-life cases
    Digitalis-based murder cases are extremely rare – or perhaps, as I mentioned earlier, the murderers have chosen their victims carefully, and the deaths have not been treated as suspicious. Agatha Christie had just one recent case to use as a possible inspiration; it occurred two years before the publication of Appointment with Death .
    In 1932, Marie Alexandrine Becker was a 55-year-old housewife who had decided that her life needed a little more excitement. Her respectable but dull life in Liège, Belgium, changed one day at the market, when she met Lambert Beyer at the vegetable stall. Beyer was something of a local lothario, and the two embarked on a tempestuous affair. The affair changed Marie from a respectable housewife to a serial killer. Her first victim was her husband, for whom she obtained a substantial payment from a life-insurance policy. Soon Marie tired of her new lover, or perhaps the money he had willed to her was too tempting; in any case, Beyer himself became her second victim.
    With the money she had obtained, Marie bought a dress shop to fund her new and