Of all drugs developed, only anti-cancer and AIDS medications are approved quickly by the US Food and Drug Administration because of the urgent need to save lives. Anti-allergy drugs, on the other hand, are examined more carefully because of the large number of potential users, so the process drags. During the process, re-testing is often necessary before submission to meet FDA requirements for the number of patients tested during clinical trials.
在各類藥物中，只有抗癌藥物和愛滋病藥物因具有挽救病患生命的急迫性，美國 FDA 審核速度會比較快；抗過敏藥則因病患族群龐大，審核較為慎重，時間拖得也比較久，其間還一度因為 FDA 要求更多臨床試驗病人數，補做試驗後再度送審。