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Radioprotective drugs

Dear Reader,

It has come to my attention that some people are promoting the use of drugs and foods which are intended to protect people against radiation. I would like to start by warning people to keep their wits about them and not to fall victim to some of the snake oil salesmen who are plying their nefarious trade.

The problem is that some of the snake oil salesmen (SOS types) and those who innocently endorse or support their products (The soviet term from Stalin’s era for such an innocent stooge was “useful idiot”) do mix some truth with the spin, wishful thinking and lies which they utter. I am going to tell you about some of the unvarnished truth about radioprotecting drugs.

One good review of radioprotectors was published recently by Céline Bourgier et. al. (C. Bourgier, A. Levy, M-C. Vozenin and E. Deutsch, Cancer Metastasis Review, 2012, DOI 10.1007/s10555-012-9381-9) in which they wrote of three classes of drug. These were

1. Radioprotectors such as amifostine

2. Mitigation drugs designed to limit the effect of radiation on normal tissues. For example Genistein is known to reduce the damage done to the lungs by radiation.

3. Drugs intended to treat the delayed effects of radiation. For example vitamin E is known to be able to reverse radiation fibrosis.

I am strongly in favor of people eating a healthy diet which contains a suitable range and amount of vitamins and minerals, while some vitamins do scavenge some reactive species formed by radiation we can reason that a poor diet could make radiation exposure more harmful we should not fall into the trap of thinking that by eating a diet packed with extra vitamins, antioxidants and other protective substances that we could then expose ourselves to radiation with impunity.

The great problem with many of these drugs is that they have unfavorable properties, for example amifostine has a short plasma lifetime so a person could never take a pill once a day to protect themselves.

Also it is known that at the wrong concentration radio protective drugs can increase the amount of damage caused by free radicals to the cells. The thiol drugs can react with the metals in the cell to generate hydrogen peroxide which then takes part in Fenton chemistry thus making reactive oxygen centred free radicals. If we want to use thiols to protect cells then this is an unwanted reaction. For details see S. Wadhwa and R.J. Mumper, Cancer Letters, 2013, 337, 8-21.

RSH –> RS. + e + H+


RS. + RS –> RSSR.-


RSSR.- + O2 –> RSSR + O2.-


O2.- + RSH + H+ –> H2O2 + RS.

Now the cycle can start all over again, as long as we have thiol the cycle can carry on making hydrogen peroxide. The oxidation product of the thiol (the disulfide RSSR) can be converted back into the thiol by nature’s version of sodium borohydride (NADPH) to allow the reaction to go on and on.

The formation of hydrogen peroxide inside cells is very bad, some years ago a cult in the far east came to my attention after some of its members started to drink hydrogen peroxide (they got ill). Trust me you do not want large amounts of hydrogen peroxide inside your body !

A wanted reaction of the thiols is to scavenge hydrogen peroxide by the following reaction,

2RSH + H2O2 –> RSSR + 2H2O

The fact that these two sets of reactions can occur means that when no thiol drug is added to the cell that the cell will operate normally (we hope in a healthy way), also when a large amount of a thiol is added to a cell then the thiol will mop up any hydrogen peroxide which is formed. But at when a small amount of the thiol is added to the cell then it can increase the amount of damage caused by hydrogen peroxide in the cell.

This feature of the thiol based radiation protection drugs suggests to me that they should not be regarded as a panacea for radiation effects. Because of the differences between normal cells and cancer cells they can be used for a short time to increase the resistance of healthy tissues to radiation thus allowing higher doses to be delivered to the cancer cells, but as a day to day prophylactic measure against cancer they do not appear to be as wonderful as they first might appear. Amifostine does alter the behavior of calcium in humans, this change sounds like a good reason not to take this drug for a prolonged length of time.

For more detail about this drug see R.L. Capizzi and W. Oster (European Journal of Cancer, 1995, 31A, Supp 1, S8-S13)

Genistein has been reported to act as a mitigator of radiation damage to the lungs, but it is also reported to be able to activate estrogen receptors. I imagine that my readers will understand instantly that this could cause all manner of trouble in men, given the choice I would rather not end up with breasts requiring me to have to wear a bra. I doubt if they would look quite right on me.

But in women estrogen receptor activators can cause havoc, sex hormones and mimics such as DES can cause a range of harmful effects. For example a steady supply of an estrogen can increase the rate at which breast cancer grows in a person, one treatment used to slow down the growth of breast cancer is to use an estrogen receptor binder which binds strongly to the receptor and does not turn it on. An example of such a drug is tamoxifen which can be used to send cancer to its room with no desert or to stick it on the naughty step. So it should be clear that an estrogen mimic could make a breast cancer case worse.

I would like to point out that cancer is not a new disease which is only associated with the “nuclear age”, it has been around for a very long time. For example Adolf Hitler’s mother died of breast cancer, I would say that the treatment which she had was not as good as what a modern women living in Sweden, the UK or Austria would get. But compared to the standard of care / treatment experienced by some women who turn their back on conventional medicine I think that Mrs Hitler had better treatment and suffered less in her final illness than they did, but I will save my thoughts on some of the alternative “treatments” for cancer for another day.

The next class of antiradiation drugs are those designed to treat the effects of radiation. The problem with these drugs is that they are not specifically drugs designed to act on cancer and they are only for use after a disease has shown its ugly face. So this class of drugs are not suitable for the prevention of cancer.

A fourth class of drug exists which can protect against radiation by reducing the amount of radioactivity inside a person or animal. The problem with these drugs is that they are element specific; a drug which works for cesium is unlikely to work for strontium. These drugs do not act on the radiation or the reactive species it forms, instead they prevent absorption of the radioisotope or increase the rate at which it is lost from a person.

While these substances might sound like science fiction miracle substances, I can say that they are real, they do work but when misapplied as a class they are far from perfectly safe or pleasant. For example in old chemistry and first aid textbooks it is suggested that the treatment for oral exposure to mercury salts should include getting the victim to swallow raw egg white. The idea is that the mercury will bind to the sulfur residues in the egg protein and thus the absorption into the person will be retarded.

As eggs in many counties are associated with salmonella I do not think that eating raw egg white is universally safe and it also does not sound an enjoyable experience to swallow a whole raw egg white. I hold the view that while working with mercury compounds and other heavy metals in my lab I will guard myself against heavy metal poisoning by mouth by making a point of avoiding hand to mouth(face) contact while working rather than eating raw eggs. I strongly suspect that the Swedish national chemical safety authority and Chalmers University will prefer it.

It has been suggested that swallowing zeolite and other inorganic solids could be used as a method of preventing a person getting heavy metal poisoning. The problem is that a habit of eating soil or clay can lead to trace metal (mineral) deficiency diseases. Harold H. Sandstead (The Journal of Trace Elements in Experimental Medicine, 2001, 14(2), 145-155) reported how clay eating resulted in people growing up to be small, weedy and sexually retarded. I am concerned that eating clay or the wrong type of zeolite ion exchanger could cause some similar metal deficiency disease in humans in the west.

As a result I think it is a bad idea for people to self-medicate with zeolites or clays, even while clays and zeolites are “natural” it does not mean that they are harmless. I think that humans who are contaminated with cesium (or think that they are cesium contaminated) should seek expert medical advice. If they are cesium contaminated then medical grade Prussian blue is a good treatment for them, this is an ion exchange solid which is specific for cesium. I have written in the past about Prussian blue here.

I would dearly like to know what the attitude of the general public is to Prussian blue, unlike zeolite it is only a manmade substance. So the nature is best brigade may not like it, one silly idea in society is that all that is manmade is evil, harmful and wrong while all natural things are good, beneficial and right.

My answer to the “natural is always perfect” is to point out that vipers, cocaine and asbestos are all natural. I can not say any of them are harmless !


2 Responses

  1. Thank you Mark, another interesting and informative post to keep the myth-makers at bay, good work!

  2. Reblogged this on AntiRadiation.

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