Answer
Capsules can lodge in and irritate the oesophagus. Plenty of water and remaining upright reduce the risk of inflammation or ulceration.
Sources for this answer
- Doxycycline 100 mg Capsules — Current selected SmPCemc · Summary of Product Characteristics
- NHSNHS · NHS medicine guidance
General medicine information. Follow the instructions for your own medicine and speak to a pharmacist or clinician about your individual circumstances.