Dosing & Uses
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
Interactions
Interaction Checker
No Results
Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor
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
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
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.
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%)
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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Patient Handout
Formulary
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