How long can I keep the novorapid (insulin aspart) flexpen out of the refrigerator?

28 days later! I assume you are referring to NovoLog Insulin flexpen, which is a product that dispenses NovoLog Insulin when a pen needle is attached to the pen. Keep unopened pens in the frig, but once opened, the pen can be used/kept at room temperature for up to 28 days. Keep your pens away from direct sunlight, hot cars (keep Insulin in a cooler when traveling). Also, never allow your Insulin to freeze!