Ultra-Rapid Insulins: A Guide

According to Ranjani Ramanathan, MD, an endocrinologist in Saint Peters, Missouri, injectable ultra-rapid insulins work about 5 to 10 minutes faster than conventional rapid insulin. Because of that, this medication, which also comes in an inhaled form, can help people be more flexible with their mealtimes.

Ultra-rapid insulins may be especially beneficial to people who have a tough time keeping their glucose in range after meals. According to Dr. Ramanathan, the three ultra-rapid insulins available are:

• Lyumjev (insulin lispro-aabc), a faster version of Humalog

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• Fiasp (insulin aspart), a faster version of NovoLog

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• Afrezza (insulin human), an inhaled insulin powder

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Lyumjev and Fiasp are delivered with a subcutaneous injection, either with an insulin pen, an insulin pump, or a vial and syringe. Afrezza is inhaled through the mouth and absorbed through the lungs, says Ramanathan.

“Ultra-rapid insulin is the same as rapid insulin, but it has additives that enable it to appear in the bloodstream faster,” says Janine Suarez, MD, an endocrinologist at the Joslin Diabetes Center in Boston.

“This is the fastest insulin to make an impact on the glucose,” says Susan Hudec, MD, an endocrinologist at Endeavor Health in Elmhurst, Illinois.

The quick action of ultra-rapid insulin is beneficial for blood sugar management, but it also provides more flexibility in administration.

“It’s important for some people to have this quick response because it allows them to inject the medication just before, during, or after meals, instead of 15 minutes before,” the typical recommendation for conventional rapid insulin, says Suarez.

“When looking at the data and clinical outcomes, these rapid onset characteristics have not been found to have clinically significant improvements in long-term glucose control and safety outcomes,” Suarez says.

Fiasp and Lyumjev, the injectable ultra-rapid insulins, can be administered with a syringe or pen, or it can be added to an insulin pump. It’s off-label to use them this way, and the drugs may cause clogs in some models, so check with your doctor regarding the specific pump you use.

The primary benefits are the same for pump users as for those injecting themselves multiple times a day: The insulin works faster, lowering glucose levels more quickly and allowing for mealtime boluses closer to the time that you actually begin eating.

Dr. Hudec believes that administering these drugs with an insulin pump with automated insulin dosing (AID) is the best therapy for patients with type 1 diabetes. “The pumps work on a closed loop with continuous glucose monitoring so you get much better overall control,” she says.

Inhaled insulin can be a good option for many people with diabetes, but it’s important to have a conversation with your care team about the benefits and drawbacks of this medication. According to Ramanathan, benefits can include:

• It’s fast. Inhaled insulin is the fastest insulin product available, which can make it easier to reduce blood sugar spikes after meals.
• Its peak ends quickly. Afrezza stops working (within 1.5 to 3 hours), which could reduce the risk of insulin stacking (administering too many insulin doses in a short period of time) and hypoglycemia.
• It doesn’t require an injection. It doesn’t require a needle for administration, which is important for those who are needle-adverse or have a needle phobia.

But inhaled insulin is very different from injectable insulin, and has some particular disadvantages.

• It’s not suitable for everyone. If you are a current smoker or have chronic lung diseases like asthma or COPD, inhaled insulin may not be the right delivery system for you.

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• It’s available only in fixed dosages. Afrezza comes in three fixed dosages: 4, 8, or 12 units, which creates less customization than subcutaneous insulin.
• It may be expensive. Inhaled insulin may not be covered by your health insurance plan.

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• It can cause different side effects. Inhaling insulin through the mouth introduces the risk of new side effects, such as cough or throat irritation.

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“Inhaled insulin offers unique benefits, such as speed and convenience, but poses challenges related to dosing flexibility, side effects, and cost that must be carefully considered by patients and healthcare providers,” says Ramanathan. You also need to monitor your pulmonary function before and while taking Afrezza.

• Ultra-rapid insulins reach peak effectiveness 5 or 10 minutes faster than conventional insulin. This provides more flexibility, allowing users to inject it just before, during, or after meals.
• The three ultra-rapid insulins available are Lyumjev, which is a faster-acting version of Humalog; Fiasp, which is a faster version of NovoLog; and Afrezza, which is an inhaled insulin powder that doesn’t require a needle to administer.
• Injectible ultra-rapid insulin drugs used along with an insulin pump and a continuous glucose monitor (CGM) may be the most effective way to stay in your target blood sugar range.