Afrezza (insulin human) is prescribed to manage blood sugar levels in adults with diabetes. The drug can cause side effects that range from mild to serious. Examples include low blood sugar levels and throat irritation.

The active ingredient in Afrezza is insulin human. The drug comes as a powder that you inhale using an inhaler device.

Keep reading to learn about common, mild, and serious side effects that Afrezza can cause. For a general overview of the drug, including details about its uses, see this article.

Afrezza has a boxed warning about the risk of sudden bronchospasm in people with lung conditions, such as asthma. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). For details, see the “Side effects explained” section.

Some people may experience mild to serious side effects during their Afrezza treatment. Examples of the drug’s commonly reported side effects include:

The following sections include more side effects of Afrezza. Each person’s experience with side effects may differ.

Mild side effects have been reported with Afrezza. These include:

  • bronchitis (swelling in the airways that carry air into and out of the lungs)
  • cough
  • diarrhea
  • fatigue
  • headache
  • nausea
  • throat pain or irritation
  • weight gain
  • mildly low blood sugar (See the “Side effects explained” section to learn more about this side effect.)

In most cases, these side effects should be temporary. And some may be managed easily. But if you have symptoms that are ongoing or bothersome, talk with your doctor or pharmacist. And do not stop Afrezza treatment unless your doctor recommends it.

Afrezza may cause mild side effects other than those listed above. See the drug’s prescribing information for details.

While rare, serious side effects have been reported with Afrezza. These include:

You can see the “Side effects explained” section to learn more about these side effects mentioned above:

  • severely low blood sugar
  • worsened lung function
  • boxed warning: risk of sudden bronchospasm in people with lung conditions

If you develop serious side effects while taking Afrezza, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911. Or call your local emergency number.

Note:After the FDA approves a drug, it tracks and reviews side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Afrezza, visit MedWatch.

Allergic reaction

For some people, Afrezza can cause an allergic reaction. But this side effect wasn’t reported in the drug’s studies.

In general, symptoms of an allergic reaction can be mild or serious.

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest a treatment to manage your symptoms. They also can determine whether you should continue Afrezza treatment.

If you have symptoms of a severe allergic reaction, such as swelling or difficulty breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

Your doctor can confirm whether you’ve had a serious allergic reaction to Afrezza. If so, they may have you switch to a different treatment.

Learn more about some of the side effects Afrezza may cause.

Low blood sugar

Mildly low blood sugar was the most common side effect reported in studies of Afrezza. Severely low blood sugar also occurred in these studies but was rare.

Low blood sugar may cause mild or severe symptoms such as:

  • dizziness
  • fatigue
  • irritable or anxious feeling
  • hunger
  • shaking
  • sweating
  • difficulty concentrating or thinking clearly
  • seizure
  • syncope (loss of consciousness)
  • coma

It’s important to note that mildly low blood sugar can become serious quickly. Sometimes it becomes serious within minutes.

Factors that can increase the risk of low blood sugar when taking this drug include:

What might help

As with any diabetes treatment, you should monitor your blood sugar regularly while taking Afrezza. Your doctor will provide more information on how you should monitor your blood sugar. They can tell you how frequently you should check it.

If you have mild symptoms

For mild symptoms of low blood sugar, immediately consume 15 grams (g) of carbohydrates that are easy to digest. Examples include:

  • 1 tablespoon of honey or sugar
  • 1/2 cup of juice or regular soda
  • 3 or 4 glucose tablets or pieces of hard candy

If you have severe symptoms

Severely low blood sugar is a medical emergency that requires immediate treatment. A prescription medication called glucagon helps treat severely low blood sugar.

For severe symptoms of low blood sugar, take a dose of glucagon. Someone else may need to give you the dose. Also, call your local emergency service right away.

Worsened lung function

Worsened lung function is a rare but possible side effect reported with Afrezza. Specifically, treatment with Afrezza over time can cause a decrease in lung function. This is measured using a spirometry test.

Symptoms of worsened lung function can include:

  • wheezing
  • persistent cough
  • shortness of breath
  • bronchospasm (tightening of the muscles lining your airways)

What might help

Before prescribing Afrezza, your doctor should check your lung health. This should include a spirometry test. They’ll want you to repeat these tests after you take Afrezza for 6 months. And they’ll repeat them at least once per year for as long as you continue treatment.

Your doctor will watch whether these tests show a decline in your lung function. They’ll also watch whether you develop symptoms of worsened lung function. If they note either, they may have you stop taking Afrezza.

Boxed warning: risk of sudden bronchospasm in people with lung conditions

Afrezza has a boxed warning about the risk of sudden bronchospasm in people with lung conditions. A boxed warning is the most serious warning from the FDA. Bronchospasm is a tightening of the muscles lining your airways.

People with asthma and chronic obstructive pulmonary disease (COPD) who used Afrezza have had sudden bronchospasm. As a result, having a long-term lung condition such as asthma or COPD is a contraindication to taking Afrezza. Contraindications are health conditions or other factors that could raise your risk of harm if you take a particular drug.

What might help

You should not use Afrezza if you have a long-term lung condition such as asthma or COPD. Instead, talk with your doctor about other treatments for diabetes that are safer for you.

Before prescribing Afrezza, your doctor should check your lung health, including using a spirometry test. If these tests reveal lung disease, your doctor likely will recommend a diabetes treatment other than Afrezza.

Keeping track of side effects

During your Afrezza treatment, consider taking notes on any side effects you’re having. You can then share this information with your doctor. This is especially helpful when you first start taking a new drug or using a combination of treatments.

Your side effect notes can include things such as:

  • what dose of the drug you were taking when you had the side effect
  • how soon you had the side effect after starting that dose
  • what your symptoms were
  • how your symptoms affected your daily activities
  • what other medications you were taking
  • any other information you feel is important

Sharing notes with your doctor will help them learn more about how Afrezza affects you. They can then use this information to adjust your treatment plan if needed.

Below is important information you should consider before taking Afrezza.

Boxed warning: Risk of sudden bronchospasm in people with lung conditions

Afrezza has a boxed warning about the risk of sudden bronchospasm in people with lung conditions. A boxed warning is the most serious warning from the FDA. For details, see the “Side effects explained” section.

Other warnings

Afrezza can sometimes cause harmful effects in people who have certain conditions. This is known as a drug-condition interaction. Other factors may also affect whether Afrezza is a good treatment option for you.

Talk with your doctor about your health history before you take Afrezza. Be sure to tell them if any of the following factors apply to you:

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.