§ Mr. LofthouseTo ask the Secretary of State for Health (1) if he has any evidence that pesticides, drugs, and toxic chemicals could be the cause of aplastic anaemia;
(2) what evidence he has available on the cause of aplastic anaemia.
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§ Mr. FreemanDifferent disorders are sometimes classified under the term appastic anaemia. In some cases the anaemia can be attributed to a chemical including some pesticides and some drugs. High doses of radiation can also give rise to this condition. In other cases, the cause cannot be determined, that is, it may occur as a disease of unknown aetiology.
We are aware of published evidence that prolonged exposure to very high levels of the industrial solvents benzene, toluene and carbon tetrachloride has been associated with the development of aplastic anaemia in some people. There is more limited evidence also that exposure to certain pesticides, namely chlordane, DDT, heptachlor, lindane, pentachloraphenol and those based on arsenic or mercury might cause aplastic anaemia.
The use of all these industrial solvents is controlled, and occupational exposures are well below those at which harm has been shown to occur. Of the pesticides, heptachlor and DDT are no longer approved for use in the United Kingdom, and the others are approved for restricted use under conditions which, as with all pesticides, should avoid harmful effects occurring.
Aplastic anaemia is recognised as a possible adverse reaction to a number of drugs. The Committee on Safety of Medicines has received from doctors over 1,000 reports associated with almost 200 medicinal products.
There is good evidence to suggest that the antibiotic drugs chloramphenicol and phenylbutazone, which are used in veterinary practice, cause aplastic anaemia in those humans sensitive to their effects. Chloramphenicol is only administered in life-threatening conditions where no suitable alternative exists.