INS and diabetes mellitus: Typically, adolescents with diabetes require 2 pens/month, with overall costs considerable higher than US$8–10 for soluble insulin, NPH insulin at $9–10, with premixed insulins at $10–15 all at 1,000 IU (i.e., 10 ml of 100 IU/ml) with each 10 ml vial lasting ~25–30 days.