Prazosin and Allopurinol Interaction
Drug interaction information between Prazosin and Allopurinol.
Prazosin and Allopurinol have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Prazosin and Allopurinol. Major interactions are generally avoided, moderate ones may need monitoring or a dose adjustment, and minor ones are usually low-risk. This page shows the documented mechanism and guidance. Label-documented interactions are not a complete safety review, so always confirm your own medications with a pharmacist or doctor. Educational information, not medical advice.
How They Interact
There is no evidence that these two medications cause problems when taken together.
What To Do
You can continue to take both of these medicines as prescribed by your doctor.
FDA Label Information
Drug Interactions Prazosin hydrochloride has been administered without any adverse drug interaction in limited clinical experience to date with the following: (1) cardiac glycosides– digitalis and digoxin; (2) hypoglycemics–insulin, chlorpropamide, phenformin, tolazamide, and tolbutamide; (3) tranquilizers and sedatives–chlordiazepoxide, diazepam, and phenobarbital; (4) antigout– allopurinol, colchicine, and probenecid; (5) antiarrhythmics–procainamide, propranolol ( see WARNINGS however), and quinidine; and (6) analgesics, antipyretics and anti-inflammatories– propoxyphene, aspirin,...
Prazosin Also Interacts With
- Aspirin minor
- Diazepam minor
- Digoxin minor
- Indomethacin minor
- Colchicine minor
Allopurinol Also Interacts With
- Pegloticase major
- Cyclosporine moderate
- Amoxicillin moderate
- Amoxicillin/Clavulanate moderate
- Warfarin minor
Frequently Asked Questions
Can I take Prazosin and Allopurinol together?
This is a minor interaction. You can continue to take both of these medicines as prescribed by your doctor.
How serious is the interaction between Prazosin and Allopurinol?
This interaction is classified as "minor" severity by the FDA. Minor interactions are unlikely to cause significant problems but should still be mentioned to your healthcare provider.
Why do Prazosin and Allopurinol interact?
There is no evidence that these two medications cause problems when taken together.
Understanding the Prazosin and Allopurinol Interaction
FDA-approved prescribing information for these two drugs flags their combination as a minor-severity interaction. Prazosin belongs to the Alpha-1 Blocker class and Allopurinol belongs to the Xanthine Oxidase Inhibitor class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: There is no evidence that these two medications cause problems when taken together. Severity tiers matter: major flags generally advise avoidance, moderate flags often require monitoring or dose adjustment, and minor flags may only call for awareness.
Context around a specific patient determines real-world impact. Prazosin has 11 total documented interactions on file in this dataset, and Allopurinol has 10. Each additional medication compounds the interaction surface, which is why pharmacists run full-profile checks rather than evaluating one pair at a time. FDA-derived guidance for this pair is: You can continue to take both of these medicines as prescribed by your doctor. Timing of doses, renal and hepatic function, age, and other concurrent prescriptions all shape whether a labeled interaction matters clinically.
An interaction flag is not a verdict. A large share of labeled interactions are managed routinely in clinical practice, the fix may be as simple as spacing doses or adding a monitoring test. Others require the prescriber to choose a different medication entirely. This page surfaces FDA-sourced labeling and openFDA data for educational purposes only; it is not medical advice and cannot account for your full clinical picture. Never start, stop, or adjust either Prazosin or Allopurinol based on a web page, speak with your prescriber or pharmacist before making any change.
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. Always consult your healthcare provider about drug interactions.
Read our methodology - how this data is sourced, computed, and verified.