Thalidomide as a Teratogen

Before 1961, there was very little evidence for drug-induced malformations in humans. But in that year, Lenz and McBride independently accumulated evidence that a mild sedative, thalidomide, caused an enormous increase in a previously rare syndrome of congenital anomalies. The most noticeable of these anomalies was phocomelia, a condition in which the long bones of the limbs are absent (amelia) or severely deficient (peromelia), thus causing the resulting appendage to resemble a seal flipper (see Figure 1.16 in Gilbert, 2000). Over 7000 affected infants were born to women who had taken this drug, and a woman need only have taken one tablet to produce children with all four limbs abnormalities induced by the ingestion of thalidomide included heart defects, absence of the external ears, and malformed intestines. The drug was withdrawn from the market in November, 1961.