Answer
Cystagon is a conventional capsule, whereas Procysbi contains gastro-resistant granules that delay release. Their food, handling and storage instructions differ.
Sources for this answer
- Cystagon 50 mg hard capsulesemc · SmPC Current selected SmPC · Version 10
- PROCYSBI 25 mg & 75 mg gastro-resistant hard capsulesemc · SmPC Current selected SmPC · Version 11