Allopurinol Injection: uric acid control, IV dosing, side effects
Last updated September 7, 2026.
**Allopurinol injection is a xanthine oxidase inhibitor, given as an infusion into a vein to lower uric acid levels.** Xanthine oxidase is the enzyme that turns purines into uric acid, so blocking it drops uric acid in your blood and urine and reduces the urate crystals that can clog the kidney tubules. The injectable form exists for people who need uric acid lowering but cannot take or keep down the oral tablets. The single most important safety point is that any new rash, fever, or mouth sore means the drug is stopped right away and your team is told, because allopurinol can set off severe skin and hypersensitivity reactions.
What does it treat?
Allopurinol injection is labeled for people with leukemia, lymphoma, or solid tumor cancers who are getting chemotherapy that drives serum and urinary uric acid up, and who cannot tolerate oral therapy. When many cancer cells break apart at once, they release purines that become uric acid, which can crystallize in the kidneys and cause acute kidney injury, so the drug is usually started before chemotherapy as part of tumor lysis syndrome prevention along with IV fluids. The oral tablets cover a wider set of uses, including gout, recurrent uric acid and calcium oxalate kidney stones, and high uric acid from cancer therapy, and most people who start on the injection are switched back to oral allopurinol once they can swallow and absorb pills. There are no combination products of injectable allopurinol; it is given as a single agent, though it is often used alongside IV hydration and sometimes rasburicase in higher risk cases.
How do you take it?
It comes as a single-dose vial of allopurinol sodium powder, usually 500 mg, which a pharmacist reconstitutes and dilutes to a concentration of 6 mg/mL or less in normal saline or dextrose, then a nurse infuses it into a vein. The adult dose in the label is 200 to 400 mg/m2 per day, based on body surface area, with a ceiling of 600 mg per day; children get 200 mg/m2 per day. The daily dose can run as one infusion or be split into equal doses at 6, 8, or 12 hour intervals, and treatment is usually started 24 to 48 hours before chemotherapy begins. If your kidneys are impaired the dose drops: about 200 mg per day at a creatinine clearance of 10 to 20 mL/min, 100 mg per day at 3 to 10 mL/min, and 100 mg at longer than daily intervals below 3 mL/min. Food rules do not apply since it bypasses the stomach, but you should take in enough fluid to produce roughly 2 liters of urine a day unless your team limits your fluids. There is no missed dose to make up at home; infusions are scheduled by your care team, so call them if you cannot make an appointment. Stop and call the same day for any rash, fever, painful mouth or eye sores, yellowing of the skin or eyes, or a sharp drop in how much you are urinating.
Side effects to know
- Common: Most people tolerate the infusion, and the effects reported most often are nausea, vomiting, rash, and irritation or pain at the infusion site.
- Serious: Stop the drug and get help for any rash at all, especially peeling or blistering skin, mouth, eye, or genital sores, or a rash with fever and swollen glands, since these can be Stevens-Johnson syndrome, toxic epidermal necrolysis, or DRESS. Also call urgently for yellowing of the skin or eyes with dark urine, a fever with sore throat or unusual bruising, or a clear drop in urine output, which point to liver injury, bone marrow suppression, or kidney injury.
Who should not take it?
Do not take allopurinol if you have had a hypersensitivity reaction to it before. Tell your doctor if you take azathioprine or mercaptopurine, since allopurinol blocks their breakdown and those doses must be cut to about one third to one fourth of normal, and if you take ampicillin or amoxicillin, which raise the chance of a rash. Warfarin and other coumarin anticoagulants, cyclosporine, theophylline, chlorpropamide, thiazide diuretics, and ACE inhibitors all need review before you start, and thiazides plus reduced kidney function raise the risk of a reaction. Kidney disease is not a reason to avoid the drug, but it does require a lower dose and closer monitoring. People of Han Chinese, Thai, or Korean ancestry more often carry the HLA-B*5801 gene variant linked to severe skin reactions, and testing is sometimes done before starting. In pregnancy, there are no adequate and well controlled studies, so the label supports use only when the benefit clearly justifies it; allopurinol and its active metabolite oxipurinol pass into breast milk, so discuss breastfeeding with your oncology team first. Alcohol raises uric acid levels and works against what this drug is doing, so skip it while you are being treated.
When is it an emergency?
Call 911 for trouble breathing, swelling of the lips, tongue, or throat, hives with lightheadedness, or collapse, which can signal anaphylaxis during or after an infusion. Call 911 or get to an emergency room for skin that is peeling or blistering, widespread rash with fever, or sores in the mouth and eyes, because severe skin reactions to allopurinol get worse fast and the drug must be stopped. For a suspected overdose, call Poison Control at 1-800-222-1222; overdose has caused nausea, vomiting, diarrhea, and dizziness, there is no specific antidote, and dialysis can remove allopurinol and oxipurinol if needed. Also seek same-day care if you stop urinating, if you turn yellow, or if you develop a fever with a sore throat while your blood counts are low from chemotherapy.
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Common questions
What is the maximum dose of allopurinol injection in a day?
For adults the label gives 200 to 400 mg/m2 per day, calculated from your body surface area, and the ceiling is 600 mg per day. Children are dosed at 200 mg/m2 per day. The daily total can be given as a single infusion or split into equal doses every 6, 8, or 12 hours. If your kidney function is reduced, the dose comes down to roughly 200 mg per day at a creatinine clearance of 10 to 20 mL/min, 100 mg per day at 3 to 10 mL/min, and 100 mg spaced further apart below 3 mL/min. Your team calculates this each cycle, so the number can change between admissions.
Can I drink alcohol while I am getting allopurinol infusions?
Skip alcohol during treatment. Alcohol raises uric acid production and reduces how much uric acid your kidneys clear, which pushes against exactly what allopurinol is doing. It also dries you out, and steady urine output is a big part of protecting your kidneys during tumor lysis prevention. Alcohol adds to nausea from chemotherapy and can strain the liver at the same time allopurinol is being monitored for liver effects. Ask your oncology team before restarting once treatment is over.
Is allopurinol injection safe during pregnancy or breastfeeding?
There are no adequate and well controlled studies of allopurinol in pregnant women, so the label supports using it only when the benefit clearly justifies the potential risk to the fetus. Tell your team if you are pregnant or might be before the first infusion, since the underlying cancer treatment plan matters just as much in that decision. Allopurinol and oxipurinol, its active metabolite, are present in breast milk. Because of that, breastfeeding is generally paused or discussed case by case with your oncologist and pediatrician. Do not stop a scheduled infusion on your own; raise it with the team first.
Do I need to change what I eat or drink on this medicine?
There are no food restrictions, because the drug goes into a vein and never passes through your stomach. Fluid matters more: aim for enough intake to produce about 2 liters of urine a day in adults, unless your team has set a fluid limit for heart or kidney reasons. Many people get IV fluids alongside the infusion for the same reason, and some protocols also work to keep the urine neutral or slightly alkaline. Cutting back on high purine foods such as organ meats, anchovies, and beer is reasonable but is not the main lever here. Alcohol should be off the list entirely.
What are the signs of taking too much allopurinol?
Reported overdose effects include nausea, vomiting, diarrhea, and dizziness. There is no specific antidote, and treatment focuses on fluids and supportive care; dialysis can pull allopurinol and oxipurinol out of the blood when the amount is large. Because the injection is prepared and given by a pharmacy and nursing team, accidental overdose is uncommon, but call Poison Control at 1-800-222-1222 right away if you think too much was given or if oral tablets were swallowed at home in excess. Call 911 instead for collapse, trouble breathing, or throat swelling. Bring the vial or bottle information with you if you go in.
Which medicines interact with allopurinol injection?
Azathioprine and mercaptopurine are the big ones: allopurinol blocks the enzyme that clears them, so their doses have to be cut to about one third or one fourth of normal to avoid dangerous bone marrow suppression. Ampicillin and amoxicillin are linked to a higher rate of rash when combined with allopurinol. Warfarin and other coumarin anticoagulants may need closer INR checks, cyclosporine levels can rise, and chlorpropamide can cause prolonged low blood sugar if your kidneys are impaired. Thiazide diuretics and ACE inhibitors have been associated with hypersensitivity reactions, especially with reduced kidney function. Give your care team a full list including over the counter products and supplements before the first infusion.