外语翻译求助

Patients were randomly assigned to ticagrelor or clopidogrel. Ticagrelor was given in a loading dose of 180 mg followed by 90 mg twice daily. Patients randomised to clopidogrel who had not received an open label loading dose and had not been taking clopidogrel for at least five days before randomisation received a 300 mg loading dose of clopidogrel study drug followed by 75 mg daily.

患者随机分为替替格瑞洛组或氯吡格雷组。 替格瑞洛使用180毫克的加载剂量，然后每天两次，每次90毫克。 随机分配给氯吡格雷的患者在随机分配前至少五天未接受开放标签负荷剂量且未服用氯吡格雷，接受氯吡格雷研究药物的剂量为300毫克，随后每天75毫克。

本段末翻译的东西不太理解，是随机分配到氯吡格雷组的患者在随机分配前至少5天未服用氯吡格雷，为什么又有300mg剂量的加载，请帮忙解答，谢谢