How long can a vial of insulin be used after it is started: where are we 10 years later?

In August 2003, I wrote a commentary entitled "How Long Can a Vial of Insulin be Used After It Is Started." The commentary included comments from each of the 3 insulin manufacturers, as well as the American Diabetes Association. Anyone reading the article quickly realized that there was little agreement among the insulin manufacturers and just as little clarity to this question. Over the ensuing 10 years, there has been little or no effort made by either the Food and Drug Administration (FDA) or the insulin manufacturers to clarify this issue of insulin storage after a bottle is started. Current package inserts list varying times from 28 to 42 days, while the latest recommendation from the American Diabetes Association gives a uniform 1-month time limit. I would therefore propose that insulin manufacturers begin putting on every insulin vial and pen, in addition to the expiration date, the amount of time that particular insulin should be used after it is started. In addition there should be a box for the patient to write the starting date directly onto the vial or pen. This would eliminate the need for uniformity of recommendations; all the patient would have to do is read the instructions written on the insulin vial or pen.