Faster Insulin Has Been Approved.  Now What?

By, Gary Scheiner MS, CDE

The US FDA has approved a faster version of aspart (brand name Novolog) for use by adults with diabetes.  Fiasp, as the product is called, stands for Faster insulin aspart.  Don’t like the name?  Tough tomatoes.  We’ve waited a long time for faster insulin, no matter what they decide to call it, and it’s finally here!

In the US, Fiasp will be sold in a FlexTouch pen and in 10 mL vials.  Fiasp has been in use throughout Europe, Canada, Australia and elsewhere for quite some time.  I managed to obtain some while traveling and have been using it for the past several months.  The good news is that it IS faster than the so-called “rapid” mealtime insulins we’ve been using for the past 15+ years.  The bad news is that it is just slightly faster.

By adding niacinamide (vitamin B3) to the formulation, the insulin molecules form monomers (single pieces of insulin) that move through the subcutaneous fat layer faster than before.  Its onset of action is about 6 minutes earlier, the peak is 7 minutes earlier, and it works 50% harder during the first 30 minutes of action compared to traditional rapid-acting insulin.  So the benefits should be obvious:  Reduced post-meal blood sugar spikes and more rapid correction of high blood sugars.

Unit-for-unit, Fiasp has the same potency as traditional rapid-acting insulin, so it should be a relatively easy conversion… and one that I would recommend to most people on pumps and multiple injection programs.

So is it a simple matter of switching over?  Unfortunately, no.  Remember, this is diabetes we’re dealing with!  Nothing is simple.  Here are a few considerations.

Can I start taking my meal (bolus) insulin after I eat?
Don’t fall into the trap of thinking “this stuff is faster… I don’t have to take it ahead of time.”  That’s like buying reduced-fat snacks and then eating the entire package because they’re “better for you.”  Users of Fiasp will still need to pay attention to the timing of their boluses.  In order to see the benefits of the faster onset, it will need to be taken at the same time you currently take your insulin.  Taking it later will negate the benefit.  However, if you already see relatively flat blood sugars after meals, you may be able to take the bolus 10 minutes later.

Do I need to avoid slowly-digesting foods?
There is potential for the blood sugar to drop when taking Fiasp and then having a large, drawn-out, or low-glycemic-index meal.  But that’s no reason to avoid them.  It will just be more important than ever to delay the injection (or use a dual/combo/extended bolus) in order to prevent post-meal hypoglycemia.

Should I adjust the duration-of-action in my insulin pump?
The duration of action setting lets the pump calculate insulin-on-board correctly.  Although Fiasp starts and peaks earlier than other insulins, its duration of action is about the same.  So you should not need to change the setting.  However, because the pump assumes a humalog/novolog/apidra action curve, it may slightly over-estimate the insulin on board during the first 30-60 minutes after a bolus is given.

What about other dosage settings?  Will those need to be adjusted?
Because the unit-for-unit potency of Fiasp is the same as other insulins, you should not need to adjust your basal rates, insulin-to-carb ratios, correction factors (sensitivity), or targets.

Is there anyone who should not use Fiasp?
Because of its relatively fast action, Fiasp can cause problems for those with gastroparesis (neuropathy that greatly slows gastric emptying), as well as those who use Symlin (an injectable medication that simulates the actions of the amylin hormone).  In both cases, Fiasp will likely work much too fast and would put the user at risk of post-meal hypoglycemia.

Will Fiasp affect my blood sugar differently during workouts?
For those who exercise after meals, the exact timing of the workout may cause changes in the blood sugar response.  Exercising within 60 minutes of taking Fiasp, the blood sugar is likely to come down more than usual, so a greater bolus reduction may be needed.  Exercising more than an hour after taking Fiasp, the blood sugar may come down less than usual, so less of an insulin reduction may be needed.  Of course, as with everything diabetes related, individual responses may vary.  It will probably take a bit of experimentation.

How easy will it be to access Fiasp?
Personally, I had to go across the border and “smuggle” my Fiasp back into the US disguised as nail polish remover.  However, obtaining Fiasp is about to become a whole lot easier.  Once Novo Nordisk makes the product available through pharmaceutical wholesalers, it should be accessible at most major (and minor) pharmacies, mostly likely in mid-to-late December.  It will be priced the same as Novolog, so health plans that currently cover Novolog should have no reason to deny it.  If your plan covers other insulins instead of Novolog, you should be able to obtain coverage by having your prescribing physician contact the health plan to obtain pre-authorization.  Because Fiasp is only approved for use in adults, children will need to have their physician write an off-label prescription and, in all likelihood, obtain pre-authorization with the insurance plan before it will be dispensed.

Switching something as important and personal as insulin represents a major change, so feel free to contact our office to discuss the details.  Any of our clinicians can work with you to set up a plan to make the conversion safe and highly beneficial.  Call 610-642-6055 to schedule an appointment by phone/internet or in-person.