Answer
Refrigerate unopened products away from the cooling element and never freeze them. Storage after first use differs between Penfill and FlexPen; follow the product leaflet and protect them from heat and light.
Sources for this answer
- Levemir Penfill 100 units/ml solution for injection in cartridge. — Current selected SmPCemc · Summary of Product Characteristics
- Levemir Flex Pen — Current selected SmPCemc · Summary of Product Characteristics