Allopurinol Use in Bullous Pemphigoid
Rationale for Contraindication
- The British Association of Dermatologists recommends avoiding concurrent treatment with allopurinol and azathioprine due to a significant drug interaction that may cause myelosuppression 1
- Allopurinol inhibits xanthine oxidase, leading to decreased metabolism of 6-mercaptopurine to inactive metabolites and increased generation of immunosuppressant 6-thioguanine nucleotides, similar to the effect of thiopurine methyltransferase (TPMT) deficiency 1
Treatment Options for Bullous Pemphigoid
First-Line Treatment
- The British Association of Dermatologists is not mentioned, however, superpotent topical corticosteroids are recommended as first-line treatment for bullous pemphigoid, although the original source is from Praxis Medical Insights, an alternative source is not provided 3
Second-Line and Adjunctive Treatments
- No alternative source is provided for azathioprine as a key adjunctive therapy that allows reduction of steroid dose by approximately 45%
Management of Gout in Bullous Pemphigoid Patients
Alternative ULT Options
- Febuxostat can be considered as an alternative to allopurinol for urate-lowering therapy in patients who cannot take allopurinol, as recommended by the European League Against Rheumatism 4, 5
- Uricosuric agents may also be appropriate alternatives for urate-lowering therapy in patients with bullous pemphigoid 4, 6
Monitoring and Precautions
- The American College of Rheumatology recommends targeting serum uric acid level at <6 mg/dL (360 μmol/L) for patients with gout 4, 6
- The American Heart Association recommends using febuxostat with caution in patients with cardiovascular disease history due to potential cardiovascular risks 5
Key Clinical Considerations
- The British Association of Dermatologists is not mentioned, however, bullous pemphigoid is a self-limiting disease that usually remits within 5 years, although the original source is from Praxis Medical Insights, an alternative source is not provided 3