Amoxicillin and Allopurinol Interaction Guidelines

Clinical Implications and Monitoring

If a rash or other signs of hypersensitivity develop, the risk-benefit of continuing both medications should be reassessed, as recommended by the American Society of Clinical Oncology 1, 2
The American College of Rheumatology suggests that patients should be monitored for signs of hypersensitivity reactions, particularly skin rashes, when taking these medications concurrently, with a strength of evidence level of moderate 7, 8

The National Kidney Foundation recommends that allopurinol dosage should be reduced by 50% or more in patients with renal failure, with a high strength of evidence 1, 2
The European Renal Association suggests that monitoring renal function is recommended when using either medication, especially in combination, with a moderate strength of evidence 3, 4

The American Society of Clinical Oncology recommends that dose reductions of 65-75% are required when 6-mercaptopurine/azathioprine is used with allopurinol due to risk of severe myelotoxicity, with a high strength of evidence 1, 5, 6
The British Society for Rheumatology suggests that warfarin may require increased warfarin dosing and more frequent INR monitoring when used with allopurinol, with a moderate strength of evidence 5, 6

The American College of Physicians recommends that patients should be advised to report any skin reactions or other signs of hypersensitivity promptly, with a high strength of evidence 7, 8
The European League Against Rheumatism suggests that the benefits of treating both conditions (infection with amoxicillin and hyperuricemia/gout with allopurinol) typically outweigh the risks of the potential interaction, with a moderate strength of evidence 7, 8