Generic Allopurinol

Common use

Allopurinol is an arthrifuge which inhibits xanthine oxidase and prevents formation of uric acid, from xanthine and hypoxanthine. Reduces the concentration of uric acid and its salts in body fluids, promotes the dissolution of existing urate deposits and prevents their formation in tissues and kidneys. The medication is used to treat diseases accompanied by hyperuricemia: gout (primary and secondary), nephrolithiasis (forming of kidney stones from urates); hyperuricemia (abnormally high level of uric acid in blood, both primary and secondary), which results in diseases involving enhanced dissolution of nucleoproteins and elevated levels of uric acid in the blood, including at various forms of leukemias, and also for treatment of some other conditions.



Dosage and direction

The dose of 100-800 mg a day may be prescribed depending on the condition. Initial dose of 100 mg can be increased gradually. Patients with acute gout and tophi (uric acid crystals in the tissues mostly around joints) should be treated with 300-400 mg of Allopuionol daily. Doses over 300 mg should be divided in two or more intakes. Take medication with food to avoid irritation of the stomach. Do not take large doses of vitamin C. Drink plenty of water to avoid formation of kidney stones. Limit consummation of alcoholic beverages and purine-rich foods such as sweetbreads, sardines, anchovies, kidneys, liver, and lentils.



Precautions

Allopurinol should be taken over a period of several months so your symptoms start to reduce. Regular intake is important even no immediate effect is noticed. You may experience acute attacks of gout more often at the beginning of treatment with Allopurinol even after normal uric acid levels are reached. The attacks will become shorter and less acute as the therapy continues. At any sign of allergic reaction stop taking the medication and consult your doctor as development of serious skin disease, irreversible damage to the liver, or generalized inflammation of a blood or lymph vessel is possible in some individuals. Inform your doctor if you have diabetes or kidney dysfunction before to take Allopurinol as correction of your dose is needed.



Contraindications

Allopurinol cannot be used in patients with hypersensitivity to the medication, in individuals with a hepatic or renal disorders, primary hemochromatosis, asymptomatic hyperuricemia, acute gout, pregnancy, lactation. The medication cannot be prescribed to children under 14 years of age unless the patients are treated for leukemia, malignant tumors and enzymatic disorders. C care. Renal failure, heart failure, diabetes mellitus, hypertension.



Possible side effect

The most common adverse reactions are diarrhea, nausea, allergy (rash, itching), and drowsiness. Stop taking the medication at first signs of rash, painful or bloody urination, eye irritation, or facial swelling, because these can be signs of a severe allergic reaction requiring immediate treatment. In rare cases Allopurinol can cause damage to nerve, kidney, and bone marrow as well as be a reason to a serious and even fatal allergic liver toxicity. In patients with liver toxicity appetite loss and itching may witness about it. The risk increases in patients with kidney impairment.



Drug interaction

The dose of oral mercaptopurine (Purinethol) and azathioprine (Imuran) should be reduced as Allopurinol increases their blood levels. Risk of skin rash increases in patients taking Allopurinol with penicillins.



Missed dose

Take the missed dose as soon as you remember unless it is almost time of your next dose. If it is almost time of your next dose just skip it and return to your regular scheme. Do not exceed the recommended dose.



Overdose

In case of suspected overdose seek for immediate medical attention. No specific information is available about Allopurinol overdose.



Storage

Store at room temperature, below 25 C (77 F) and out of reach and children and pets.



Disclaimer

We provide only general information about medications which does not cover all directions, possible drug integrations, or precautions. Information at the site cannot be used for self-treatment and self-diagnosis.All specific instructions for a particular patient should be agreed with your health care adviser or doctor in charge of the case. We disclaim reliability of this information and mistakes it could contain. We are not responsible for any direct, indirect, special or other indirect damage as a result of any use of the information on this site and also for consequences of self-treatment.

Clinical Verification

Last Clinically Updated: August 15, 2026

Written By

Dr. Elena Vance, PharmD

Clinical Specialist in Neuropharmacology

Fact Checked By

Marcus Thorne, MS

Biomedical Data & FDA Label Verification

Medically Reviewed By

Dr. Arthur Campbell, MD

Board-Certified Psychiatrist (ABPN)