User blog comment:Xilinoc/Ch. 566 (not out yet, but dis gon b gud)/@comment-4794735-20140201215800/@comment-11051098-20140202132233

Akon or whoever it was in the SRDI said that they managed to send the Shin'eiyaku pills to every Shinigami who has Bankai (I think). So naturally both Byakuya and Renji got them too. Maybe the RG as well.