In late 1959, it was noticed that peripheral neuritis developed in patients who took the drug over a period of time, and it was only after this point that thalidomide ceased to be provided over the counter.
A finais de 1959, detectouse que se orixinaba neurite periférica en pacientes que tomaran o fármaco durante un período de tempo, e só despois disto a talidomida deixou de ser vendida sen receita.