Allopurinol

32 interactions 333 cited references
Also sold as: Aloprim Lopurin® Zyloprim Zyloprim®
About Allopurinol

Allopurinol is used to treat gout (a type of arthritis in which uric acid, a naturally occurring substance in the body, builds up in the joints and causes sudden attacks of redness, swelling, pain, and heat in one or more joints). Allopurinol is also used to treat high levels of uric acid that builds up in the blood as… Read the full Allopurinol drug information page →

Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Updated Jul 12, 2026 · Editorial policy · Data sources

Sources: FDA prescribing information (Structured Product Labeling), the published literature cited in each entry, DDInter 2.0 (a major open-access drug-interaction database), and legacy DrugBank interaction data distributed by the NIH's RxNav service (decommissioned in 2024) — analyzed and reviewed by our pharmacist team. How we build this library →

Most serious with: Didanosine Fezolinetant Acenocoumarol Azathioprine Capecitabine Pegloticase Injection
2 Contraindicated 22 Major 7 Moderate 1 Minor
All (32) Contraindicated (2) Major (22) Moderate (7) Minor (1)

Contraindicated

Allopurinol Didanosine Videx® Increased serum concentrations of didanosine Details Allopurinol Fezolinetant Increased fezolinetant exposure Details

Major

Allopurinol Acenocoumarol Increased INR Details Allopurinol Azathioprine Azasan An increased risk of myelosuppression, an increased risk of hepatotoxicity and an azaTHIOprine toxicity (nausea, vomiting, leukope... Details Allopurinol Capecitabine Xeloda Reduced capecitabine or doxifluridine or fluorouracil (prodrugs of capecitabine) or tegafur (prodrug of fluorouracil) exposure and... Details Allopurinol Captopril Capoten® Hypersensitivity reactions (Stevens-Johnson syndrome, skin eruptions) Details Allopurinol Clomipramine Anafranil Increased clomiPRAMINE exposure Details Allopurinol Doxifluridine Reduced capecitabine or doxifluridine or fluorouracil (prodrugs of capecitabine) or tegafur (prodrug of fluorouracil) exposure and... Details Allopurinol Enalapril Epaned Hypersensitivity reactions (Stevens-Johnson syndrome, skin eruptions, anaphylactic coronary spasm) Details Allopurinol Enalaprilat Hypersensitivity reactions (Stevens-Johnson syndrome, skin eruptions, anaphylactic coronary spasm) Details Allopurinol Fluorouracil Adrucil Reduced capecitabine or doxifluridine or fluorouracil (prodrugs of capecitabine) or tegafur (prodrug of fluorouracil) exposure and... Details Allopurinol Levoketoconazole Recorlev Increased risk of serious hepatotoxicity and drug-induced liver injury Details Allopurinol Mercaptopurine Purinethol® An increased risk of myelosuppression, an increased risk of hepatotoxicity and an azaTHIOprine toxicity (nausea, vomiting, leukope... Details Allopurinol Methotrexate Jylamvo Increased methotrexate exposure, an increased risk of methotrexate-related severe adverse reactions, reduced active metabolite for... Details Allopurinol Pegloticase Increased risk of anaphylaxis and infusion reactions Details Allopurinol Phenprocoumon Increased INR Details Allopurinol Pimozide Increased pimozide exposure and an increased risk of pimozide-related adverse reactions Details Allopurinol Tegafur Reduced capecitabine or doxifluridine or fluorouracil (prodrugs of capecitabine) or tegafur (prodrug of fluorouracil) exposure and... Details Allopurinol Tizanidine Increased tiZANidine exposure and an increased risk of tiZANidine-related hypotension, bradycardia or increased drowsiness Details Allopurinol Warfarin Coumadin Increased INR Details Allopurinol Fluorouracil Injection Adrucil Reduced capecitabine or doxifluridine or fluorouracil (prodrugs of capecitabine) or tegafur (prodrug of fluorouracil) exposure and... Details Allopurinol Fluorouracil Topical Carac Reduced capecitabine or doxifluridine or fluorouracil (prodrugs of capecitabine) or tegafur (prodrug of fluorouracil) exposure and... Details Allopurinol Methotrexate Injection Abitrexate® Increased methotrexate exposure, an increased risk of methotrexate-related severe adverse reactions, reduced active metabolite for... Details Allopurinol Pegloticase Injection Krystexxa Increased risk of anaphylaxis and infusion reactions Details

Moderate

Allopurinol Aluminum Hydroxide AlternaGEL® Decreased allopurinol effectiveness Details Allopurinol Anisindione An increased risk of bleeding Details Allopurinol Cyclosporine Atopica Increased cycloSPORINE exposure Details Allopurinol Theophylline Accurbron® Theophylline toxicity (nausea, vomiting, palpitations, seizures) Details Allopurinol Vidarabine Neurotoxicity, tremors, impaired cognitive function Details Allopurinol Cyclosporine Injection Atopica Increased cycloSPORINE exposure Details Allopurinol Cyclosporine Ophthalmic Cequa Increased cycloSPORINE exposure Details

Minor

Allopurinol Probenecid An increase in probenecid concentration Details

Check another drug

Still have questions about this combination?

Every question gets a real answer from a licensed pharmacist — free, and usually within a day.

Ask the pharmacist
Educational information only, not medical advice. Always confirm interactions with your pharmacist or prescriber before making any change to your medications.