DISASTER LED TO DRUG STUDY

Press, Volume CVI, Issue 31090, 20 June 1966, Page 1

DISASTER LED TO DRUG STUDY

Since the thalidomide disaster, much literature had been compiled about the effects of a large number of deformity-producing drugs, Dr. D. Poswillo, a Christchurch oral surgeon, told the annual conference of the Pharmaceutical Society of New Zealand on Saturday.

“The magnitude of this problem of deformity is indicated by the fact that in the Western world one baby in every 50 is born with a major malformation,” he said. The literature about the drugs, he said, should at least make manufacturers aware of the very wide range of substances that had been shown to have deformity producing effects in animals and perhaps in humans.

Dr. Poswillo was speaking about the toxic action of drugs on unborn children to 140 pharmacists from throughout New Zealand.

He said doctors could only decide that a drug was definitely capable of producing malformations in humans on the basis of past information which was not always very reliable.

But when the frequency of an abnormality was greater in babies produced by mothers treated by a particular drug than in those born to mothers not so treated, a relationship between the drug and deformity was considered to exist. On A Tight-Rope Dr. Poswillo said that because of the difficulty of proving or dirproving isolated case reports, doctors sometimes found themselves walking a tight-rope. "We must acknowledge that drugs with valuable therapeutic properties should not be wholly discarded because under certain conditions they may have ill effects,” he said. “In deciding whether to use such a suspected drug on a

pregnant woman, the severity of a possible foetal defect and the frequency of its occurrence inust be balanced against the risks of not giving the drug or of giving a substitute drug. “The risk to the foetus of using the drug and risk to the mother of not using it must all be assessed and balanced against the other.” Dr. Poswillo emphasised that the dose of th drug and the time of administration could both be critical factors.

To high a dose of a de-formity-producing drut. could kill a foetus and be followed by abortion. The more the foetus had developed the less dramatic would be the evidence of disability when the child was born. Some drugs, however, seemed to obey no rules and might produce major deformities even if given in a single dose over a considerable span of time. Animal Tests Dr. Poswillo said experiments made on animals to test drugs could be misleading but doctors could not wilfully interfere with thed evelopment of a human foetus to obtain information about deformity producing drugs. There was evidence of an

unknown factor or factors of an environmental nature Involved in determining malformation. Vitamin deficiencies could produce deformities while excessive doses of vitamin D had been associated with mental and heart defects and a peculiar facial appearance. “If a drug is under suspicion at all, the only guarantee of safety from adverse effects is not to prescribe at all,” he said. Some drugs taken by the mother might interfere with the adjustment of the baby in the first few days after birth. Narcotics might produce severe withdrawal symptoms in the baby equivalent to those experienced by people being treated for addiction.

Dr. Poswillo said reports of suspected deformity-produc-ing activity should be made to the Council on Adverse Reactions which would ensure that the possible deformity was immediately understood by all interested parties. Dr. Poswillo said it was fortunately improbable that the circumstances of the thalidomide disaster would ever be repeated. “Good might come from the tragedy if in consequence there is a greater awareness of the unsolved problems of congenital malformation and of the special care needed in prescribing for women who may be pregnant,” he said.