Answer
XL tablets release quetiapine over a longer period and have specific food and swallowing instructions. Standard tablets release it more quickly; do not substitute one for another without confirmation.
Sources for this answer
- Biquelle XL 200mg prolonged-release tablets — Current selected SmPCemc · Summary of Product Characteristics
- Quetiapine 300 mg Film-coated Tablets — Current selected SmPCemc · Summary of Product Characteristics