The Importance of Insulin

Most of us don’t give insulin much thought. After we eat a meal, our pancreas automatically releases insulin, which moves sugar (glucose) out of the blood and into the cells so it can either be used immediately for energy or stored in cells for later use.

But in people with type 1 diabetes, the pancreas doesn’t make insulin. In type 2 diabetes, the body either doesn’t make enough insulin, doesn’t use it effectively, or, most commonly, both. People with type 1 diabetes need to take insulin to replace the hormone their body is lacking. Those with type 2 diabetes may need to take insulin to help keep their blood sugars within the target range.

Insulin can’t be taken in pill form because the stomach would start to break down the medicine before it had a chance to work. So up to now, people with diabetes have most often taken insulin via injection. People who need insulin have to give themselves one or more injections daily.

In recent years, there’s been a breakthrough in insulin delivery systems. A new form of insulin is now allowing people with diabetes to take their insulin by inhaling it. Although inhaled insulin won’t replace injections any time soon, it could reduce the number of shots some people have to take.

What Is Inhaled Insulin?

Inhaled insulin is dissolved in a dry powder, which is placed inside a single-dose cartridge. You breathe in the powder through a small inhaler, similar to an asthma inhaler. The insulin gets absorbed into your lungs, and it moves from there into your bloodstream.

A few different versions of inhaled insulin have been studied over the years. In 2006, Exubera was the first inhaled insulin to be FDA-approved for sale in the United States. Yet just a year later, its manufacturer, Pfizer, pulled it from the market because of poor sales. Other companies pulled their inhaled insulin products even before they went to market. In 2014, the FDA approved a new inhaled insulin product called Afrezza. It’s expected to be available to the public by 2015.

Benefits and Risks

Inhaled insulin comes with benefits, but it has some downsides, too.

Benefit: It Works Fast

Inhaled insulin starts to work quickly. It goes into action about 15 minutes after you take it at the start of a meal, similar to rapid-acting insulin. In comparison, short-acting insulin generally has a 30- to 60-minute onset. While both inhaled and rapid-acting insulin begin working quickly, rapid-acting insulin can last up to 3-5 hours, while inhaled insulin is removed from the body in 2-3 hours. This quicker elimination may help reduce the risk of low blood sugar and weight gain.

Risk: It Increases Risk for DKA

According to the medication’s prescribing information published by the FDA, Afrezza increases a person’s risk for diabetic ketoacidosis (DKA). DKA occurs when substances called ketones build up in the blood. DKA is a potentially dangerous complication. If it’s not treated, it can even be fatal.

Compared with other types of insulin, the inhaled drug led to DKA more often in people with type 1 diabetes. If you’re at increased risk for DKA, make sure to talk to your doctor about possible complications of inhaled insulin.

Benefit: It’s Effective

In people with type 1 diabetes, Afrezza controlled blood sugar as well as rapid-acting injected insulin. In those with type 2 diabetes, it improved blood sugar control further when added to oral diabetes medicines.

Risk: It Has Side Effects

Some of the main side effects of inhaled insulin involve the lungs. In fact, Afrezza carries a boxed warning about the risk of bronchospasm, which is a sudden muscle spasm in the airway that can make it hard to breathe. For this reason, it’s not recommended for people with asthma or chronic obstructive pulmonary disease (COPD), or for those who smoke.

Some people who have taken inhaled insulin have experienced a slight drop in lung function. A 2007 study published in Diabetes Technology and Therapeutics looked into the effects of inhaled insulin on lung function. Researchers studied people with both type 1 and type 2 diabetes who did not have lung disease. They found that, compared with injected insulin and oral drugs, inhaled insulin led to a small decrease in lung function. However, lung function didn’t worsen over time.

According to Afrezza prescribing information, the same is true for the new drug. People using Afrezza also experienced a small decline in lung function. The manufacturer noted there is currently not enough evidence to determine if stopping the medication improves lung function. They also advise doctors to assess a person’s lung function on an ongoing basis.

Other, mild side effects of inhaled insulin include a cough and sore throat. More long-term studies are needed to determine the long-term effects of inhaled insulin on the lungs.

Benefit: It Limits Some Side Effects of Injected Insulin

Sometimes insulin can bring down blood sugar levels so much that it leads to low blood sugar. While inhaled insulin can also have this side effect, it might be less of a risk due to the shorter life span of inhaled insulin. The inhaled version might also reduce the risk of weight gain, which is another common side effect of injected insulin.

Deciding Whether to Use Inhaled Insulin

Inhaled insulin might take some of the sting out of treating diabetes, but it won’t entirely replace the injected form. If you use long-term insulin to help control your blood sugar levels, you will still need to inject this insulin.

Weigh the benefits and risks of inhaled insulin with your doctor. Together, you can decide whether this is the right treatment option for you.