allopurinol (Rx)

Brand and Other Names:Zyloprim, Aloprim
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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  

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Interactions

Interaction Checker

and allopurinol

No Results

     activity indicator 
    No Interactions Found
    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

          Minor

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            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

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            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)

            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

            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

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            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.

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            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%)

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            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)

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            Formulary

            FormularyPatient Discounts

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