Answer
Beta-blockers, including some glaucoma eye drops, can weaken formoterol's effect. They should be reviewed rather than stopped without medical advice.
Sources for this answer
- Trixeo Aerosphere 5 micrograms/7.2 micrograms/160 micrograms pressurised inhalation, suspension — 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.