[Insulin consumption in Norway 1975-89. How much did the change to insulin 100 cost?]

The consumption of the various types of insulin in the period 1975-89 has been examined. Norway changed from insulin U-40 to insulin U-100 on 1 April 1987. This led to a marked increase in sales of insulin. Sales from the Norwegian Medicinal Depot (the national drug wholesale monopoly) in 1989 were 23% higher than average sales for the three years preceding the change (1984-86). This increase represents a retail value of NOK 59 million. The main reason for the increase is probably a disproportionate relationship between the amount of insulin in each vial (10 ml) and the recommended deadline for using the rest of the insulin in the vial after the first withdrawal. This has most likely led to an extensive discarding of vials containing surplus insulin. Vials with a smaller volume (5 ml) and/or re-assessment of the recommended lifespan of an opened vial might decrease the amount of insulin discarded as waste.