What is the most important information I should know about Afrezza? Afrezza can cause serious side effects including: Sudden lung problems (bronchospasms). Do not use Afrezza if you have long-term (chronic) lung problems such as asthma or chronic obstructive pulmonary disease (COPD). Before starting Afrezza, your healthcare provider will perform a detailed medical history, physical examination, and will give you a breathing test (called spirometry) to check how your lungs are working.