Take the most recent diltiazem drip rate, multiply it by 3, then add 3, then multiply that by 10. That equals the total daily dose so divide by 4 to get the q 6 hrs oral dose. In equation form:
(diltiazem IV gtt rate x 3 + 3 ) x 10 = total daily po dose, divide by 4 for q 6 hr PO dose