Answer
Yes. Serious allergic reactions can occur within hours or occasionally days after an injection. Breathing difficulty, swelling, collapse or severe dizziness requires emergency help.
Sources for this answer
- Fasenra 30 mg solution for injection in pre filled pen — Current selected SmPCemc · Summary of Product Characteristics
General medicine information. Follow the instructions for your own medicine and speak to a pharmacist or clinician about your individual circumstances.