Short answer: Afrezza has a boxed warning: acute bronchospasm has been seen in people with asthma or COPD, so it is not used with chronic lung disease, and spirometry is done before starting. Besides low blood sugar, cough was the most common side effect: 26% of adults with type 2 diabetes (20% on placebo) and 29% with type 1 (5% on injected insulin). Cough was the top reason people stopped (3%).
What Afrezza is approved for: Afrezza is an inhaled mealtime insulin approved to improve blood sugar control in adults and children 6 years and older with diabetes (section 1). It is not recommended for diabetic ketoacidosis, and not recommended in people who smoke or have recently stopped smoking.
Source
AFREZZA (insulin human) inhalation powder, for oral inhalation use, prescribing information, Medication Guide and Instructions for Use. MannKind Corporation. DailyMed, version published June 26, 2026. DailyMed setid 29f4637b-e204-425b-b89c-7238008d8c10
WARNING: RISK OF ACUTE BRONCHOSPASM IN PATIENTS WITH CHRONIC LUNG DISEASE
Acute bronchospasm has been observed in Afrezza-treated patients with asthma and chronic obstructive pulmonary disease (COPD). Afrezza is contraindicated in patients with chronic lung disease such as asthma or COPD. Before starting Afrezza, a detailed medical history, physical examination and spirometry (FEV1) are done in all patients to identify potential lung disease (Boxed Warning, sections 2.1, 4 and 5.1).
These are the label's own numbers from the Adverse Reactions section. Where the label compares with placebo (a dummy treatment), both columns are shown, so you can see how much more often a reaction happened on Afrezza.
| Adverse reaction | AFREZZA, % (n=1,991) | Placebo, % (n=290) | Non-placebo comparators, % (n=1,363) |
|---|---|---|---|
| Cough | 26 | 20 | 5 |
| Throat pain or irritation | 4 | 4 | 1 |
| Headache | 3 | 3 | 2 |
| Diarrhea | 3 | 1 | 2 |
| Productive cough | 2 | 1 | 1 |
| Fatigue | 2 | 1 | 1 |
| Nausea | 2 | 0.3 | 1 |
Pooled controlled trials. The placebo was the carrier particle without insulin.
| Adverse reaction | AFREZZA, % (n=1,026) | Subcutaneous insulin, % (n=835) |
|---|---|---|
| Cough | 29 | 5 |
| Throat pain or irritation | 6 | 2 |
| Headache | 5 | 3 |
| Pulmonary function test decreased | 3 | 1 |
| Bronchitis | 3 | 2 |
| Urinary tract infection | 2 | 2 |
Pooled active-controlled trials against injected insulin.
| Hypoglycemia severity | AFREZZA (N=177) | Placebo (N=176) |
|---|---|---|
| Severe hypoglycemia | 5% | 2% |
| Non-severe hypoglycemia | 67% | 30% |
| Adverse reaction | AFREZZA, % (n=117) | RAA, % (n=113) |
|---|---|---|
| Cough | 21 | 3 |
| Upper respiratory tract infection | 18 | 14 |
| Oropharyngeal pain | 11 | 4 |
| Headache | 8 | 5 |
| Vomiting | 5 | 3 |
26-week open-label trial against a rapid-acting insulin analog (RAA), both with basal insulin; 97.8% had type 1 diabetes. The label says the study was not designed for meaningful comparisons of side-effect rates.
About 27% of adults on Afrezza reported cough, against about 5% on comparators. Cough was the most common reason for stopping Afrezza (3% of adults).
Over up to 2 years, adults on Afrezza had a 40 mL (95% CI -80, -1) greater fall in FEV1 than on comparators. It appeared in the first 3 months and persisted. A fall of 15% or more happened in 6% on Afrezza against 3% on comparators.
In people with asthma whose bronchodilators were briefly withheld, bronchoconstriction and wheezing followed an Afrezza dose in 29% (5 of 17), against 0% (0 of 13) without asthma. FEV1 fell by a mean of 400 mL 15 minutes after one dose in asthma, and by 200 mL 18 minutes after one dose in 8 people with COPD.
Two cases of lung cancer occurred in trials in 2,750 patient-years on Afrezza, both with a history of heavy smoking, against none in 2,169 patient-years on comparators. Two more cases in non-smokers were reported after the trials ended. The label says the data are insufficient to tell whether Afrezza affects lung tumors.
In type 1 diabetes trials, diabetic ketoacidosis was more common on Afrezza (0.43%, 13 people) than on comparators (0.14%, 3 people).
In a type 2 trial, people on Afrezza gained a mean 0.49 kg while those on placebo lost a mean 1.13 kg. In the children's trial, severe (level 3) low blood sugar occurred in 2 children on Afrezza (1.7%) and 1 on RAA (0.9%).
Reported after approval: bronchospasm.
The Warnings and Precautions part of the label lists these. Each line gives the label's heading and what it means in plain words.
Who should not use it. Afrezza is not used during an episode of low blood sugar, by people with chronic lung disease such as asthma or COPD, or by people who have had a severe allergic reaction to any regular human insulin or Afrezza's inactive ingredients.
Acute bronchospasm in chronic lung disease. Sudden narrowing of the airways has been seen in people with asthma and COPD. A medical history, physical exam and spirometry (FEV1) are done before starting to look for lung disease.
Changes in insulin regimen. Changing insulin strength, maker, site, type or method can cause high or low blood sugar, so changes are made under close medical supervision with more glucose checks.
Low blood sugar. Hypoglycemia is the most common reaction to insulin, and severe episodes can cause seizures or death. Afrezza's time-action profile affects when lows happen. Awareness of lows may be reduced with long diabetes, nerve damage, beta-blockers or repeated lows.
Decline in lung function. Afrezza causes a small decline in FEV1 over time. Lung function is checked at baseline, after the first 6 months and yearly after that, even without symptoms. Stopping is considered with a fall of 20% or more from baseline, and Afrezza is stopped if breathing symptoms persist.
Lung cancer. For people with active or past lung cancer, or at risk of it, the label says to weigh whether Afrezza's benefits outweigh this possible risk.
Diabetic ketoacidosis. People with type 1 diabetes always use Afrezza with a basal insulin. In people at risk of DKA, such as with acute illness or infection, glucose is checked more often and switching to another way of giving insulin is considered.
Serious allergic reactions. Severe, life-threatening whole-body allergy, including anaphylaxis, can occur; Afrezza is stopped if it does.
Low potassium. All insulins shift potassium into cells and can cause low potassium, which untreated can cause breathing paralysis, heart rhythm problems and death.
Heart failure with TZDs. Thiazolidinediones (such as pioglitazone) with insulin can cause fluid retention that may lead to or worsen heart failure.
From the Medication Guide that comes with Afrezza:
Dose Track has a side-effect log. Each entry records the symptom, a severity (none, mild, moderate, severe or life-threatening), the date and an optional note, and can be tied to a specific dose or logged on its own. The history screen shows what you logged over time, which makes it easier to tell your prescriber when a reaction started and whether it is easing. The app records what you enter; it does not judge whether a symptom is serious. For anything on the label's call-your-doctor list, call your doctor.
This page is what the FDA label says, in plain words. It is not medical advice. Follow your prescriber, and ask them or your pharmacist about anything here.