by Jessica Pyhtila, PharmD, BCPS, BCGP
When you think of insulin, you probably think of an injectable medication that you give yourself either with a syringe, insulin pen, or insulin pump. However, an alternative exists. Powdered insulin, also known as inhaled insulin, is a less-common product that nonetheless has a role in diabetes management.
What is Powdered Insulin?
Powdered insulin is sold under the brand name Afrezza. The product is an inhaler that takes cartridges of powdered short-acting insulin. It can be used in both Type 1 diabetes and Type 2 diabetes. However, it does not replace long-acting insulin and must be used alongside a long-acting insulin in those with Type 1 diabetes.
The active ingredient in Afrezza is short-acting human insulin. It additionally contains fumaryl diketopiperazine and polysorbate 80, which are the excipients, or the medium through which the drug is mixed and therefore able to be administered.
At this time, no generic equivalent for Afrezza is available. For this reason, powdered insulin can be expensive: 180 cartridges can cost almost $1500. However, a manufacturer prescription savings program is available that can reduce your copay to $15 if you have commercial insurance coverage.
Is Powdered Insulin Safe and Effective?
- Has a quicker onset
- Wears off more quickly
- May lead to fewer instances of low blood sugar
- May cause less weight gain
Like any drug, powdered insulin has some side effects. These include:
- Hypoglycemia, occurring in up to 67% of people on the drug
- Cough, impacting around 27% of people on the drug. This was the most common reason people chose to stop taking Afrezza in clinical trials.
- Throat pain, which happens in 4.4% of people on Afrezza
- Headache, occurring in 3.1% of people on the drug
How Long Does Powdered Insulin Work?
Powdered insulin is short-acting human insulin, and is, therefore, generally restricted to mealtime use. It does not replace long-acting insulin. The exact onset and wearing-off times of powdered insulin depend on the dose you are taking:
|Afrezza 4 units||Afrezza 12 units||Afrezza 48 units|
|Approximate time to peak blood-sugar-lowering effect||35 minutes||45 minutes||55 minutes|
|Approximate time to fully wear off||90 minutes||180 minutes||270 minutes|
Can I Use Powdered Insulin if I Have a Lung Condition?
You cannot use powdered insulin if you have lung problems, including asthma or COPD. This is because powdered insulin can cause both a decline in lung function and bronchospasm, a contraction of the airways. This can make it very difficult to breathe if you have an underlying lung problem. For this reason, your doctor will perform a breathing test before you get a powdered insulin prescription to make sure your lungs are working normally.
For similar reasons, powdered insulin should be avoided in people who smoke, as well as those who have quit smoking within the past 6 months. Powdered insulin should also be avoided in those with a history of lung cancer.
Even if you have normal lung function and no history of lung disease, your doctor will keep a close eye on your lung function due to the link between powdered insulin and a decline in lung function. Your doctor will therefore have you perform breathing tests after 6 months of therapy on powdered insulin and annually thereafter.
Even if you have only mild lung issues, it is important to be cautious with powdered insulin if you take it with other inhaled drugs. For example, studies have shown that taking albuterol while you are on powdered insulin can significantly increase the amount of insulin in your body.
Can I Use Powdered Insulin if I Am Pregnant or Breastfeeding?
There is very little data available for the impact of powdered insulin in pregnant or breastfeeding women and their babies. Your doctor will need to balance the possible risks of powdered insulin against the known risks of high blood sugar and uncontrolled diabetes in pregnancy.
That said, there is no clear link between powdered insulin and any pregnancy harm, including birth defects and miscarriage. Doctors believe that the ingredients in powdered insulin likely get into a mother’s breastmilk. However, the risks linked to inhaling powdered insulin, like lung function problems, are unlikely to be present if the baby is exposed via another route like breastmilk.
How Do You Use Powdered Insulin?
Although powdered insulin’s administration is obviously different from other short-acting insulins, like other short-acting insulins, it should be taken at the beginning of a meal.
Afrezza comes as an inhaler with single-use cartridges in 3 different strengths:
- 4 units of human insulin (blue cartridge)
- 8 units of human insulin (green cartridge)
- 12 units of human insulin (yellow cartridge)
Because powdered insulin is only available in preset quantities of 4, 8, and 12 units, a person’s dosing must reflect the available cartridges. A person who needs more than 12 units of insulin will need to use multiple cartridges to achieve the necessary dose. For example, a person who needs 20 units of insulin would need to use both an 8-unit green cartridge and a 12-unit yellow cartridge to add up to 20 units.
Powdered insulin’s dosing may be slightly different from that of injectable insulins: for this reason, dosage adjustments may be needed if you are switching to powdered insulin from another insulin product. If you have never before been on insulin, the usual starting dose of powdered insulin is 4 units inhaled at the start of a meal.
Afrezza is a dry-powder inhaler, meaning that it does not spray out of the device like, for example, some asthma inhalers. Instead, the inhaler is breath-powered, meaning the person must inhale deeply from the inhaler’s mouthpiece in order to breathe in the drug.
Powdered Insulin vs Powdered Inulin
It is important to remember that powdered insulin is a prescription-only product. Searching for it on sites like Amazon will bring you to a similarly-named over-the-counter product called inulin, which is a different substance altogether.
Inulin is a prebiotic intended for oral use only. A prebiotic is a supplement that provides nourishment for beneficial bacteria in your gastrointestinal tract. As a supplement, it has not been evaluated or approved by the FDA for the treatment of any medical condition. As such, inulin is not a replacement for insulin. That said, some small studies have shown that inulin may help to control blood sugars in people with diabetes. Further studies are still pending, but for now, inulin does not have a routine place in diabetes management.
For those who prefer to not self-inject their short-acting insulin, powdered insulin may be an alternative treatment to help manage diabetes. However, downsides of powdered insulin include lung-related side effects including a decrease in lung function. If you are wondering if you are a good candidate for powdered insulin, consider discussing the option of powdered insulin with your doctor.