Thalidomide: Acting on Early Warnings

The U.S. Food and Drug Administration (FDA) usually takes a precautionary approach to approving new medicines that includes testing for health impacts and efficacy before marketing. For example, from 1957 to 1961, the drug thalidomide was marketed in many other countries as a sleeping pill and as a treatment for morning sickness in pregnant women.

When taken by pregnant women, thalidomide turned out to cause devastating birth defects, including phocomelia, a deformity in which a baby is born without arms or legs. The drug is estimated to have produced deformities in over 10,000 children in 46 countries before it was taken off the market.

People in the U.S. were largely spared this tragedy, thanks to precautionary action by an FDA physician, Frances Kelsey. Kelsey did not have proof of thalidomide’s toxic effects, but based on limited information about the drug, she wondered whether thalidomide could have serious effects in fetuses that might not show up in adults. When presented with a routine application to market the drug in the U.S., Kelsey decided to delay approval and request additional information from the manufacturer.

In hindsight, it seems obvious that thalidomide should have been tested for effects on fetuses before, not after, it was prescribed to pregnant women. FDA now requires companies to test drugs for harmful effects on fetuses before putting them on the market. But thousands of industrial chemicals that enter the bodies of infants, children, and pregnant women through water, air, and consumer products are not pre-tested for safety – and should be.