thalidomide
n. a drug reintroduced into the United States in 1998 as an immunosuppressant for treatment of cutaneous manifestations of erythema nodosum leprosum (a severe, acute form of leprosy). A derivative of the sedative glutethimide, it was originally (in the late 1950s and early 1960s) used to treat anxiety and morning sickness in pregnancy until its association with severe, life-threatening birth defects became apparent. Numerous fetal abnormalities—including abnormal limb development (see phocomelia) and gastrointestinal, cardiac, and neurological deficits—were common and the drug was withdrawn. Prescription requires special training by prescribers and pharmacists, and thalidomide must not be taken by women who are pregnant; both women and men who are taking thalidomide must comply with various conditions and contraceptive measures. Its mechanism of action is unclear. U.S. trade name: Thalomid.