Along this path, many potential drugs are withdrawn, and even successfully tested drugs face the additional hurdle of regulatory approval. Finally, the drug reaches the market, where it must be followed closely, because many adverse reactions are detected only with a large number of patients and after years of use.
在这一过程中，许多潜在的药物被放弃，即便是成功通过试验的药物也面临着额外的监管审批障碍。最后，药物进入市场，也必须对其进行严格跟踪，因为许多不良反应要经过众多病人多年的使用之后才能被发现。