With many insulin formulations on the market, it can be hard to differentiate between similar-acting products and what the best choice may be for our patients. One question raised is what the differences between Novolog versus Fiasp are due to both being insulin aspart formulations.
The main difference is right in the name of Fiasp. F-Faster I– Insulin ASP– Aspart. Fiasp and Novolog contain the same active ingredient portion of insulin aspart, but Fiasp has an added component of vitamin B3 (niacinamide) that helps to increase how fast the body absorbs the insulin making it work quicker. Other minor differences when comparing Fiasp versus Novolog include a component for added stability of l-arginine. The product website compares the two regarding onset times and states that Fiasp is 2x quicker than Novolog.
Novolog Versus Fiasp – Administration Timing
A major bonus for patients taking Fiasp insulin is that they can have more flexibility around the timing of their dosing at mealtimes due to this quicker onset. Fiasp can be taken right before a meal, or within 20 minutes of starting a meal. This is beneficial to patients who don’t know how much of a meal they are going to eat. It takes some of the guessing out of how many carbs are going to be consumed which in theory improves insulin-to-carb dosing. It also is beneficial when going out to eat due to unpredictable service times of food and not having to dose in advance of a meal. Comparatively, Novolog needs to be taken about 5-10 minutes before the start of a meal.
Novolog and Fiasp – Insulin Pumps
In diabetic patients using an insulin pump, Fiasp is not approved for use in all pumps at this time. Medtronic and Tandem pumps such as T-slim have approved only Humalog and Novolog for use. One system that does have Fiasp as approved is Omnipod. The Omnipod user manual states Fiasp in its list of insulins to be used in the system for up to 3 days.
Novolog Versus Fiasp – Cost Comparison
Cost can vary based on insurance formularies, coupons available, and wholesalers. Fiasp is newer to the market and brand name so it may be more expensive compared to generic insulin aspart or even Novolog. Retail pricing review at GoodRx puts Novolog cash price in the 300-400 dollar range while Fiasp is listed up above 600 dollars for many listed locations.
In summary, with the comparison of Novolog and Fiasp, Fiasp is quicker in its onset and can help with variable mealtimes. Fiasp cannot be used in all pumps which could be a barrier to use with a patient established on a pump. Novolog may be less expensive and the higher cost of Fiasp may also limit its use in some situations.
This article was written by Leah Lowenberg in collaboration with Eric Christianson, PharmD, BCPS, BCGP
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Medtronic. (n.d.). Diabetes – indications, safety, and warnings. https://www.medtronic.com/us-en/healthcare-professionals/products/diabetes/indications-safety-warnings.html
Omnipod User Guide. (n.d.). https://www.omnipod.com/sites/default/files/2021-04/Omnipod-System_User-Guide_English.pdf
Insulin compatibility. (n.d.-a). https://support.tandemdiabetes.com/hc/en-us/articles/1500011397082-Insulin-Compatibility
What is Fiasp®?: FIASP® (insulin aspart) injection 100 u/ML. What is Fiasp®? | Fiasp® (insulin aspart) injection 100 U/mL. (n.d.). https://www.mynovoinsulin.com/insulin-products/fiasp/get-to-know-fiasp/about-fiasp.html