If the medication or fluid calculators do not appear to be working properly and are showing a total dose or maintenance rate of 0, check to ensure your patient has a weight entered other than zero.  If the patient weight is zero, the calculator cannot function (since the number 0 times anything equals zero).

Update the patient's weight and then go back into the calculator.  Tapping on the dosage (for drugs) or the maintenance rate (for fluids) should update the calculator with the new weight, and allow it to work properly.