Understanding Afrezza Side Effects

Afrezza is an inhaled insulin used to control blood sugar in adults with type 1 or type 2 diabetes. Because you breathe it into your lungs rather than inject it, Afrezza has a unique side effect profile compared to other insulins. Knowing what to expect can help you feel more prepared and know when something needs medical attention.

If you are new to Afrezza, you may also want to read What Is Afrezza? Uses, Dosage, and What You Need to Know for a broader overview.

Common Side Effects of Afrezza

The following side effects are reported frequently in clinical trials. Most are mild and tend to improve as your body gets used to the medication:

• Cough — This is the most common side effect. Most patients experience a mild, dry cough shortly after inhalation. It usually decreases over time.
• Sore throat — Irritation in the throat is common, especially during the first few weeks.
• Hypoglycemia (low blood sugar) — Like all insulins, Afrezza can cause low blood sugar. Symptoms include shakiness, sweating, confusion, and dizziness.
• Headache — Some patients report mild headaches.
• Diarrhea — Digestive upset may occur.
• Fatigue — Feeling tired is sometimes reported.
• Nausea — Mild stomach discomfort is possible.
• Bronchitis — Upper respiratory symptoms may occur.
• Urinary tract infection — UTIs have been reported in clinical studies.
• Weight gain — As with most insulin therapies, some weight gain is possible.

Managing Common Side Effects

Dealing With the Cough

The cough is the side effect that surprises most new Afrezza users. Here is what helps:

• Take a sip of water before and after inhaling
• Inhale slowly and steadily through the device
• Know that the cough usually decreases significantly after the first 2-4 weeks
• If the cough is severe or does not improve, talk to your doctor

Preventing Hypoglycemia

Low blood sugar is a risk with any insulin. To reduce your risk:

• Take Afrezza at the beginning of your meal, not before you start cooking
• Do not skip meals after dosing
• Keep fast-acting glucose (juice, glucose tabs) nearby
• Monitor your blood sugar regularly, especially when starting or adjusting your dose

Serious Side Effects: When to Get Help Immediately

While rare, some side effects require immediate medical attention:

Acute Bronchospasm

Afrezza carries a boxed warning about the risk of acute bronchospasm — a sudden tightening of the muscles around your airways. This is most dangerous for people with asthma or COPD, which is why Afrezza is contraindicated in those patients. If you experience sudden wheezing, difficulty breathing, or chest tightness after inhaling Afrezza, seek emergency medical care immediately.

Severe Hypoglycemia

Severe low blood sugar can cause confusion, seizures, or loss of consciousness. If you or someone you are with cannot treat the low blood sugar by eating or drinking, call 911. Make sure people around you know how to use glucagon if you have been prescribed it.

Hypokalemia (Low Potassium)

Insulin can shift potassium into cells, lowering blood potassium levels. Symptoms include muscle weakness, cramps, and irregular heartbeat. This is more common at higher doses or when combined with other medications that lower potassium.

Allergic Reactions

Severe allergic reactions (anaphylaxis) are rare but possible. Signs include rash, swelling of the face or throat, difficulty breathing, and rapid heartbeat. Seek emergency help if you suspect an allergic reaction.

Decline in Lung Function

Afrezza may cause a gradual decline in pulmonary function over time. This is why your doctor will order regular spirometry tests. A small decrease in FEV1 has been observed in clinical trials. If you notice increasing shortness of breath over time, report it to your doctor.

Afrezza and Lung Cancer

During clinical trials, a small number of lung cancer cases were reported among Afrezza users. While no direct causal link has been established, the FDA recommends monitoring. If you have a history of lung cancer, discuss the risks with your doctor before starting Afrezza.

Who Should NOT Take Afrezza?

Afrezza is not safe for everyone. It is contraindicated in:

• Patients with asthma or COPD
• During episodes of hypoglycemia
• People with a hypersensitivity to human insulin or any of Afrezza's ingredients
• Current smokers or those who recently quit smoking

For more on who should avoid Afrezza, see our article on Afrezza drug interactions.

Side Effects Compared to Injectable Insulin

If you are considering switching from injectable insulin (like Humalog, NovoLog, or Fiasp) to Afrezza, here is how the side effects compare:

• No injection site reactions — Since Afrezza is inhaled, you avoid pain, bruising, and lipodystrophy at injection sites.
• Cough and throat irritation — These are unique to Afrezza and not seen with injectable insulins.
• Faster onset, shorter duration — Afrezza acts within 12-15 minutes and wears off faster, which may reduce the risk of late postmeal hypoglycemia compared to injected rapid-acting insulins.
• Lung function monitoring — Required for Afrezza but not for injectable insulins.

Learn more about how Afrezza compares to alternatives in our guide: Alternatives to Afrezza.

When to Call Your Doctor

Contact your healthcare provider if you experience:

• Cough that does not improve after a few weeks or gets worse
• Increasing shortness of breath
• Frequent episodes of low blood sugar
• Signs of infection (fever, persistent sore throat)
• Any new or worsening symptoms

Call 911 or go to the emergency room for:

• Severe difficulty breathing or wheezing after inhalation
• Severe hypoglycemia with confusion or loss of consciousness
• Signs of a serious allergic reaction (facial swelling, throat closing)

Tracking Your Side Effects

Keeping a simple log of any side effects you notice — when they happen, how severe they are, and how long they last — can help your doctor make better decisions about your treatment. Many diabetes apps let you track symptoms alongside your blood sugar readings.

If you are having trouble finding Afrezza at your pharmacy, check our guide on how to check if a pharmacy has Afrezza in stock or use MedFinder to search availability near you.