Answer
It can uncommonly affect liver tests and rarely cause hepatitis or serious blood-cell disorders. Yellowing, unexplained bruising, bleeding, fever or persistent sore throat need assessment.
Sources for this answer
- NHSNHS · NHS medicine guidance
- Allopurinol Tablets BP 100mg — Current selected SmPCemc · Summary of Product Characteristics
- Allopurinol 100mg — Current selected SmPC