If you've entered the dosage for a drug in the medication calculator and the total dose does not seem to be updating, or it updates but shows the wrong amount, you may have incorrectly entered one of the parameters in the dosage or concentration drop down lists.

In the example below, the dosage of this medication was entered as 2.5 mg/kg.  You can see that the Total dose comes out to the same number: 2.5.  Based on the patient weight of 35 kg, we know this total dosage is incorrect.

In this case, it is because there was a space entered after the "kg" in the dosage section.  This is not easily noticeable when you are looking at the calculator, but the calculator cannot recognize the space and therefore will not function properly.  If you click on the drop down list again, you will now see that there are two parameters that look the same, but are actually different (one has a space after it, the other doesn't).  When you've selected the incorrect parameter, you will be able to see the space after it in the dosage section because your cursor will flash at the end of the space.

Take a look at the image below to see the error:

When entering concentrations and dosages, try to select the value from the drop down list if possible, to reduce the chances of encountering this error.  To fix this issue, simply select the correct parameter from the dropdown list, and the calculator will update automatically.  Be sure to delete the incorrect parameter by determining which one it is on the list, then sliding it to the left and clicking on the red "Delete" button that appears.