It is much simpler to consider does size as a number of tablets rather than in MG. Using MG dosage requires the user to back calculate based on the MG per tablet listed on the box then multiply out the number of tablets from the prescription.

It might be better to have the option to enter MG per tablet (if it is a tablet based medication, or per drop if it is liquid based or ml for the powerful injected ones)

Then the rest of the does info could be provided as a max/min number to tablets per day, max/min number of per dose.