Short answer: Keep both unopened in the fridge at 36°F to 46°F (2°C to 8°C) until the expiration date, and never use them after freezing. Out of the fridge, a Humalog Mix50/50 KwikPen lasts 10 days in total, up to 86°F (30°C). A Novolin 70/30 vial lasts 42 days up to 77°F (25°C); a FlexPen 28 days up to 86°F (30°C). In-use pens and opened Novolin vials are not refrigerated.
Both are cloudy premixed insulins. Section 16.2 of each: Humalog Mix50/50 says “Protect from direct heat and light. Do not freeze and do not use if it has been frozen.” Novolin 70/30 says “Do not expose NOVOLIN 70/30 vials and NOVOLIN 70/30 FlexPen to excessive heat or light. Do not freeze. Do not use after the expiration date.”
| Form | Unopened, refrigerated | Unopened, room temperature | In use (opened) |
|---|---|---|---|
| Humalog Mix50/50 3 mL KwikPen | Until expiration date | 10 days (up to 86°F [30°C]) | 10 days, room temperature only (do not refrigerate) |
| Novolin 70/30 10 mL vial | Until expiration date | 42 days up to 77°F (25°C) | 42 days up to 77°F (25°C) (do not refrigerate) |
| Novolin 70/30 3 mL FlexPen | Until expiration date | 28 days up to 86°F (30°C) | 28 days up to 86°F (30°C) (do not refrigerate) |
Humalog Mix50/50 footnote: “When stored at room temperature, HUMALOG Mix50/50 KwikPen can only be used for a total of 10 days including both not in-use (unopened) and in-use (opened) storage time.” A pen that sat out unopened for 4 days has 6 days left once you start it.
Section 16.1 lists only the KwikPen (five 3 mL pens). The same label still carries vial Instructions for Use with vial storage rules: unopened vials in the fridge until the expiration date, “Unopened vials should be thrown away after 28 days, if they are stored at room temperature,” and “Store opened vials in the refrigerator or at room temperature up to 86°F (30°C) for up to 28 days.” Those 28-day vial rules do not appear in section 16. If you have a pharmacy-dispensed vial, ask your pharmacist which label came with it.
KwikPen Instructions for Use: “Store unused Pens in the refrigerator at 36°F to 46°F (2°C to 8°C).” “Unused Pens stored at room temperature, up to 86°F (30°C), should be thrown away after 10 days.” “Store the Pen you are currently using at room temperature [up to 86°F (30°C)]. Keep away from heat and light.” Throw it away after 10 days, even if insulin is left.
That is what the table gives; the label does not explain it. The vial and the FlexPen have different limits:
Neither Patient Information leaflet has its own storage section; the storage lines are in the Instructions for Use.
Both are suspensions that “must be resuspended immediately before use”, which is easier at room temperature (section 2). Humalog Mix50/50 KwikPen: roll it at least 10 times, then invert it at least 10 times until it looks evenly white and cloudy. Novolin 70/30 vial: roll it gently in your hands in a horizontal position 10 times; FlexPen: move it up and down 20 times so the glass ball moves end to end. Inject right away.
See Humalog Mix50/50 dosing, Humalog Mix50/50 side effects, Novolin 70/30 dosing, Novolin 70/30 side effects, Humalog Mix50/50 vs Mix75/25 and NovoLog Mix vs Novolin 70/30.
An in-use Humalog Mix50/50 KwikPen travels at room temperature up to 86°F (30°C) for the rest of its 10 days. A Novolin 70/30 FlexPen gets 28 days up to 86°F (30°C); a Novolin 70/30 vial 42 days but only up to 77°F (25°C), so keep vials out of hot cars and sun. Unopened spares start their count when they leave the fridge.
More in the travel guide.