Since 9/20/16 Afib Dx, Rx W/ Xarrelto, 20mg, And Diltiazem

Since 9/20/16 Afib Dx, Rx w/ Xarrelto, 20mg, and diltiazem 24hr ER, 240mg. Submitted my cardiologist's 90 day Rx for Xarelto to Express Scripts & it is being questioned re "other drug interactions", ergo, order being held. I do not have renal nor liver impairment, nor am I diabetic. Due for cardio follow up 11/2.
This is request for 2nd opinion. Thank you, Chuck S.