allopurinol (Rx)

Brand and Other Names:Zyloprim, Aloprim
  • Print

Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

tablet

  • 100mg
  • 300mg

powder for injection

  • 500mg/vial

Gout

Mild: 100 mg/day PO initially; increased weekly to 200-300 mg/day

Moderate to severe: 100 mg/day PO initially; increased weekly to 400-600 mg/day

Antineoplastic-Induced Hyperuricemia

PO: 600-800 mg divided q8-12hr, starting 1-2 days before chemotherapy

IV: 200-400 mg/m²/day; not to exceed 600 mg/m²/day; may administer as single infusion or in equally divided doses at 6, 8, 12 hr intervals beginning 1-2 days before chemotherapy  

Dosing Considerations

Minimum PO dosage: 100-200 mg/day

Maximum PO dosage: 800 mg/day

Dosing Modifications

Renal impairment

  • CrCl 10-20 mL/min: 200 mg/day
  • CrCl 3-10 mL/min: 100 mg/day
  • CrCl <3 mL/min: 100 mg/day at extended intervals

Dosage Forms & Strengths

tablet

  • 100mg
  • 300mg

powder for injection

  • 500mg/vial

Hyperuricemia

10 mg/kg/day PO divided q12hr; not to exceed 600 mg/day  

Antineoplastic-Induced Hyperuricemia

PO (<6 years): 150 mg/day divided q8hr

PO (6-10 years): 300 mg/day in single daily dose or divided q8hr

PO (>10 years): 600-800 mg/day, starting 1-2 days before chemotherapy

IV: 200 mg/m²/day initially, starting 1-2 days before chemotherapy  

Next:

Interactions

Interaction Checker

and allopurinol

No Results

     activity indicator 
    No Interactions Found
    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

          Minor

            All Interactions Sort By:
             activity indicator 

            Contraindicated (0)

              Serious - Use Alternative (11)

              • azathioprine

                allopurinol increases levels of azathioprine by decreasing metabolism. Avoid or Use Alternate Drug. Increased risk of bone marrow toxicity.

              • benazepril

                benazepril increases toxicity of allopurinol by unspecified interaction mechanism. Avoid or Use Alternate Drug. May increase risk for allergic or hypersensitivity reactions to allopurinol. Monitor for symptoms of hypersensitivity reactions if both drugs must be used together.

              • captopril

                captopril, allopurinol. Mechanism: unknown. Avoid or Use Alternate Drug. Risk of anaphylaxis, Stevens Johnson syndrome.

                captopril increases toxicity of allopurinol by Mechanism: unspecified interaction mechanism. Avoid or Use Alternate Drug. May increase risk for allergic or hypersensitivity reactions to allopurinol Monitor for symptoms of hypersensitivty reactions if both drugs must be used together.

              • didanosine

                allopurinol increases levels of didanosine by unknown mechanism. Contraindicated.

              • enalapril

                enalapril, allopurinol. Mechanism: unknown. Avoid or Use Alternate Drug. Risk of anaphylaxis, Stevens Johnson syndrome.

              • perindopril

                perindopril, allopurinol. Mechanism: unknown. Avoid or Use Alternate Drug. Risk of anaphylaxis, Stevens Johnson syndrome.

              • pexidartinib

                allopurinol and pexidartinib both increase Other (see comment). Avoid or Use Alternate Drug. Pexidartinib can cause hepatotoxicity. Avoid coadministration of pexidartinib with other products know to cause hepatoxicity.

              • pretomanid

                allopurinol, pretomanid. Either increases toxicity of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Pretomanid regimen associated with hepatotoxicity. Avoid alcohol and hepatotoxic agents, including herbal supplements and drugs other than bedaquiline and linezolid.

              • protamine

                allopurinol increases effects of protamine by decreasing metabolism. Avoid or Use Alternate Drug.

              • theophylline

                allopurinol increases levels of theophylline by decreasing metabolism. Avoid or Use Alternate Drug.

              • warfarin

                allopurinol increases effects of warfarin by decreasing metabolism. Avoid or Use Alternate Drug.

              Monitor Closely (14)

              • acalabrutinib

                acalabrutinib, allopurinol. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration may increase risk of myelosuppressive effects.

              • aluminum hydroxide

                aluminum hydroxide decreases levels of allopurinol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

              • amoxicillin

                allopurinol decreases toxicity of amoxicillin by Other (see comment). Use Caution/Monitor. Comment: Allopurinol may increase potential for allergic or hypersensitivity reactions to amoxicillin.

              • calcium carbonate

                calcium carbonate decreases levels of allopurinol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

              • cyclophosphamide

                allopurinol increases toxicity of cyclophosphamide by decreasing metabolism. Use Caution/Monitor.

              • dichlorphenamide

                dichlorphenamide and allopurinol both decrease serum potassium. Use Caution/Monitor.

                dichlorphenamide, allopurinol. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Both drugs can cause metabolic acidosis.

              • ethambutol

                ethambutol decreases effects of allopurinol by Other (see comment). Use Caution/Monitor. Comment: Hyperuricemia reported with ethambutol and precipitation of gout reported; uric acid lowering agents may be require dosage adjustment.

              • hydroxyurea

                allopurinol, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • mercaptopurine

                allopurinol increases levels of mercaptopurine by decreasing metabolism. Use Caution/Monitor. Potential for increased myelosuppression.

              • methotrexate

                allopurinol decreases effects of methotrexate by Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • mipomersen

                mipomersen, allopurinol. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Both drugs have potential to increase hepatic enzymes; monitor LFTs.

              • sodium bicarbonate

                sodium bicarbonate decreases levels of allopurinol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

              • sodium citrate/citric acid

                sodium citrate/citric acid decreases levels of allopurinol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

              • thioguanine

                allopurinol, thioguanine. unknown mechanism. Use Caution/Monitor. Potential for increased myelosuppression.

              Minor (3)

              • ampicillin

                ampicillin, allopurinol. Mechanism: unknown. Minor/Significance Unknown. Increased incidence of rash.

              • cyclosporine

                allopurinol increases levels of cyclosporine by unknown mechanism. Minor/Significance Unknown.

              • tacrolimus

                allopurinol increases levels of tacrolimus by unknown mechanism. Minor/Significance Unknown.

              Previous
              Next:

              Adverse Effects

              1-10%

              Rash (1.5%)

              Nausea (1.3%)

              Renal failure (1.2%)

              Vomiting (1.2%)

              Frequency Not Defined

              Amblyopia

              Arthralgias

              Blood dyscrasias

              Bronchospasm

              Cardiovascular abnormalities

              Cataracts

              Confusion

              Decrease in libido

              Dizziness

              Ecchymosis

              Electrolyte abnormalities

              Epistaxis

              Foot drop

              Hematuria

              Hepatotoxicity

              Hypotonia

              Iritis

              Kidney function abnormality

              Macular retinitis

              Malaise

              Neuritis

              Pharyngitis

              Pruritus

              Skin edema

              Stevens-Johnson syndrome

              Sweating

              Tinnitus

              Previous
              Next:

              Warnings

              Contraindications

              Hypersensitivity to allopurinol

              Cautions

              Discontinue at first sign of allergic reactions (first sign of rash, vasculitis, or Stevens-Johnson syndrome, drug rash with eosinophilia and systemic symptoms (DRESS) and/or generalized vasculitis, irreversible hepatotoxicity)

              The HLA-B*58:01 allele is a genetic marker for severe skin reactions indicative of hypersensitivity to allopurinol; patients who carry the HLA-B*58:01 allele are at a higher risk of allopurinol hypersensitivity syndrome (AHS); however, hypersensitivity reactions reported in patients who do not carry this allele; frequency of this allele is higher in individuals of African, Asian (e.g., Han Chinese, Korean, Thai), and Native Hawaiian/Pacific Islander ancestry; prior to starting therapy, consider testing for the HLA-B*58:01 allele in genetically at-risk populations; therapy not recommended in HLA-B*58:01 positive patients unless benefits clearly outweigh risks

              Myelosuppression reported; use caution when administering other drugs known to cause myelosuppression

              Hepatotoxicity (reversible) reported

              Not for treatment of asymptomatic hyperuricemia

              Use with caution in renal impairment

              Risk of hypersensitivity increased in patients treated with angiotensin-converting emzyme (ACE) inhibitors

              When taken with amoxicillin or ampicillin, may increase risk of skin rash

              During concomitant treatment, reduce dosages of azathioprine and mercaptopurine to 25-33% of usual

              Occurrence of hypersensitivity reactions may be increased in patients with renal impairment, especially in patients who are receiving thiazide diuretics; reduce dose in patients with impaired renal function

              Risk of hypersensitivity may increase with concomitant administration of thiazides

              Maintain fluid intake necessary to yield urine output of at least 2 L/day in adults

              Previous
              Next:

              Pregnancy & Lactation

              Pregnancy

              Experience with human pregnancy limited partly because women of reproductive age rarely require treatment with drug; in 2011, a literature publication case report describes outcome of a full term pregnancy in a 35 year-old woman who had recurrent kidney stones since age 18 who took allopurinol throughout pregnancy; the child had multiple complex birth defects and died at 8 days of life; a second report on 31 prospectively ascertained pregnancies involving mothers exposed to allopurinol for varying durations during first trimester; the overall rate of major fetal malformations and spontaneous abortions was reported to be within normal expected range; however, one child had severe malformations similar to those described in earlier case report

              Animal data

              • Reproductive studies performed in rats and rabbits at doses up to twenty times usual human dose (5 mg/kg per day) concluded that there was no impaired fertility or harm to fetus due to allopurinol; there is a published report of a study in pregnant mice given 50 or 100 mg/kg allopurinol intraperitoneally on gestation days 10 or 13; there were increased numbers of dead fetuses in dams given 100 mg/kg allopurinol but not in those given 50 mg/kg; there were increased numbers of external malformations in fetuses at both doses of allopurinol on gestation day 10 and increased numbers of skeletal malformations in fetuses at both doses on gestation day 13; it cannot be determined whether this represented a fetal effect or an effect secondary to maternal toxicity; there are, however, no adequate or well controlled studies in pregnant women; because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed

              Lactation

              Allopurinol and oxipurinol have been found in milk of mother who was receiving drug; since effect of allopurinol on nursing infant is unknown, exercise caution when therapy is administered to nursing woman

              Pregnancy Categories

              A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

              B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

              C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

              D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

              X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

              NA: Information not available.

              Previous
              Next:

              Pharmacology

              Mechanism of Action

              Xanthine oxidase inhibitor; inhibits conversion of hypoxanthine to xanthine to uric acid; decreases production of uric acid without disrupting synthesis of vital purines

              Pharmacokinetics

              Bioavailability: 49-53%

              Onset: 2-3 days

              Peak plasma time: 0.5-2 hr

              Time to peak effect: 7-14 days

              Distribution

              Protein bound: <1%

              Vd: 1.6-2.4 L/kg

              Metabolism

              Metabolized in liver

              Metabolites: Oxypurinol (active), allopurinol riboside (activity unknown)

              Elimination

              Half-life: Parent drug, 1-3 hr; active metabolite, 15-20 hr

              Dialyzable: Yes (both hemodialysis and peritoneal dialysis)

              Renal clearance: 30 mL/min

              Total body clearance: 16 mL/min/kg

              Excretion: Urine (80%), feces (10-20%)

              Previous
              Next:

              Administration

              IV Compatibilities

              Y-site (partial list): Acyclovir, calcium gluconate, cefazolin, ceftriaxone, carboplatin, cisplatin, cyclophosphamide, dactinomycin, doxorubicin liposomal, fluorouracil, ifosfamide, mesna, metronidazole, mitoxantrone, morphine sulfate, potassium chloride, thiotepa, vancomycin

              IV Incompatibities

              Y-site: Amikacin, amphotericin B, carmustine, cefotaxime, chlorpromazine, cimetidine, clindamycin, cytarabine, dacarbazine, daunorubicin, diphenhydramine, doxorubicin, doxycycline, droperidol, floxuridine, gentamicin, haloperidol, hydroxyzine, idarubicin, imipenem-cilastatin, mechlorethamine, meperidine, methylprednisolone sodium succinate, metoclopramide, minocycline, nalbuphine, netilmicin, ondansetron, prochlorperazine, promethazine, sodium bicarbonate, streptozocin, tobramycin, vinorelbine

              IV Preparation

              Reconstitute with 25 mL SWI

              Dilute to desired concentration with NS or D5W; do not use sodium bicarbonate-containing solutions; final concentration of ≤6 mg/mL is recommended

              Store solution at 20-25°C (do not refrigerate), and use within 10 hours after reconstitution

              IV Administration

              In both adults and children, daily dose can be given as single infusion or in equally divided infusions q6hr, q8hr, or q12hr

              Whenever possible, administration should be initiated 1-2 days before start of chemotherapy known to cause tumor cell lysis (including adrenocorticosteroids)

              Previous
              Next:

              Images

              BRAND FORM. UNIT PRICE PILL IMAGE
              Zyloprim oral
              -
              100 mg tablet
              Zyloprim oral
              -
              300 mg tablet
              allopurinol oral
              -
              100 mg tablet
              allopurinol oral
              -
              300 mg tablet
              allopurinol oral
              -
              100 mg tablet
              allopurinol oral
              -
              100 mg tablet
              allopurinol oral
              -
              300 mg tablet
              allopurinol oral
              -
              100 mg tablet
              allopurinol oral
              -
              300 mg tablet
              allopurinol oral
              -
              100 mg tablet
              allopurinol oral
              -
              100 mg tablet
              allopurinol oral
              -
              300 mg tablet
              allopurinol oral
              -
              300 mg tablet
              allopurinol oral
              -
              300 mg tablet
              allopurinol oral
              -
              100 mg tablet
              allopurinol oral
              -
              100 mg tablet
              allopurinol oral
              -
              300 mg tablet
              allopurinol oral
              -
              100 mg tablet
              allopurinol oral
              -
              300 mg tablet
              allopurinol oral
              -
              300 mg tablet
              allopurinol oral
              -
              100 mg tablet
              allopurinol oral
              -
              300 mg tablet

              Copyright © 2010 First DataBank, Inc.

              Previous
              Next:

              Patient Handout

              Patient Education
              allopurinol oral

              ALLOPURINOL - ORAL

              (AL-oh-PURE-i-nol)

              COMMON BRAND NAME(S): Zyloprim

              USES: Allopurinol is used to treat gout and certain types of kidney stones. It is also used to prevent increased uric acid levels in patients receiving cancer chemotherapy. These patients can have increased uric acid levels due to release of uric acid from the dying cancer cells. Allopurinol works by reducing the amount of uric acid made by the body. Increased uric acid levels can cause gout and kidney problems.

              HOW TO USE: Take this medication by mouth, usually once daily or as directed by your doctor. Take this medication after a meal to reduce stomach upset. If your dose is more than 300 milligrams a day, you will need to take several smaller doses during the day to get this amount (ask your doctor for directions).It is best to drink a full glass of water with each dose and at least 8 more glasses (8 ounces each) of fluid a day. If your doctor has directed you to drink less fluid for other medical reasons, consult your doctor for further instructions. Your doctor may also instruct you on how to decrease acid in your urine (e.g., avoiding large amounts of ascorbic acid/vitamin C).Dosage is based on your medical condition and response to treatment. Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time(s) each day.For the treatment of gout, it may take up to several weeks for this medicine to have an effect. You may have more gout attacks for several months after starting this medicine while the body removes extra uric acid. Allopurinol is not a pain reliever. To relieve pain from gout, continue to take your prescribed medicines for gout attacks (e.g., colchicine, ibuprofen, indomethacin) as directed by your doctor.Tell your doctor if your condition persists or worsens.

              SIDE EFFECTS: Stomach upset, nausea, diarrhea, or drowsiness may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor right away if you have any serious side effects, including: numbness/tingling of arms/legs, easy bleeding/bruising, unusual tiredness, signs of kidney problems (such as change in the amount of urine, painful/bloody urination), signs of liver disease (such as nausea/vomiting that doesn't stop, loss of appetite, stomach/abdominal pain, yellowing eyes/skin, dark urine), unusual weight loss, eye pain, vision changes.Allopurinol may rarely cause very serious (possibly fatal) skin reactions. Some people in certain ethnic groups (such as people of African, Asian, or Native Hawaiian/Pacific Islander descent) are at greater risk. Your doctor may order a blood test to measure your risk before you start this medication. If the blood test shows you are at greater risk, your doctor should discuss the risks and benefits of allopurinol and other treatment choices with you. Get medical help right away if you develop any symptoms of a serious skin reaction, including: skin rash/blisters/peeling, itching, or swelling. Ask your doctor or pharmacist for more details.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: fever, swollen lymph nodes, rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

              PRECAUTIONS: Before taking allopurinol, tell your doctor or pharmacist if you are allergic to it; or if you have had a severe reaction to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: liver disease, kidney disease, diabetes, high blood pressure (hypertension), unusual diets (e.g., fasting).This drug may make you drowsy. Alcohol or marijuana (cannabis) can make you more drowsy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Alcohol may also decrease the effectiveness of this drug. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.Allopurinol passes into breast milk. Consult your doctor before breast-feeding.

              DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (such as prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Some products that may interact with this drug are: "blood thinners" (e.g., warfarin), capecitabine, didanosine.

              OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.

              NOTES: Do not share this medication with others.Laboratory and/or medical tests (e.g., uric acid blood levels, liver/kidney function tests, complete blood count) may be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.If you are taking allopurinol to treat kidney stones, you may benefit from a special diet. Consult your doctor for more details.

              MISSED DOSE: If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

              STORAGE: Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

              Information last revised August 2021. Copyright(c) 2021 First Databank, Inc.

              IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.

              Previous
              Next:

              Formulary

              FormularyPatient Discounts

              Adding plans allows you to compare formulary status to other drugs in the same class.

              To view formulary information first create a list of plans. Your list will be saved and can be edited at any time.

              Adding plans allows you to:

              • View the formulary and any restrictions for each plan.
              • Manage and view all your plans together – even plans in different states.
              • Compare formulary status to other drugs in the same class.
              • Access your plan list on any device – mobile or desktop.

              The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

              Tier Description
              1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
              2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
              3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
              4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
              5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
              6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
              NC NOT COVERED – Drugs that are not covered by the plan.
              Code Definition
              PA Prior Authorization
              Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
              QL Quantity Limits
              Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
              ST Step Therapy
              Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
              OR Other Restrictions
              Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
              Additional Offers
              Email to Patient

              From:

              To:

              The recipient will receive more details and instructions to access this offer.

              By clicking send, you acknowledge that you have permission to email the recipient with this information.

              Email Forms to Patient

              From:

              To:

              The recipient will receive more details and instructions to access this offer.

              By clicking send, you acknowledge that you have permission to email the recipient with this information.

              Previous
              Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.