Allopurinol
Pronouncation: (AL-oh-PURE-ee-nahl)Class: Agent for gout, Antimetabolite
Trade Names:
Aloprim
- Powder for injection, lyophilized 500 mg
Trade Names:
Zyloprim
- Tablets 100 mg
- Tablets 300 mg
Novo-Purol (Canada)
Pharmacology
Feedback for Allopurinol
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Inhibits xanthine oxidase, the enzyme responsible for conversion of hypoxanthine to xanthine and then to uric acid.
Pharmacokinetics
Absorption
About 90% absorbed from GI tract. T max is 1.5 h (allopurinol) and 4.5 h (oxipurinol). C max is 3 mcg/mL (allopurinol 300 mg) and 6.5 mcg/mL (oxipurinol).
Metabolism
Rapidly oxidized to oxipurinol.
Elimination
About 20% is excreted in the feces. Allopurinol is essentially cleared by glomerular filtration, whereas oxipurinol is reabsorbed in the kidney tubules. T 1/2 , plasma is about 1 to 2 h (allopurinol) and about 15 h (oxipurinol).
Onset
Uric acid decreases in about 2 to 3 days.
Peak
May require a week or more of treatment.
Duration
Xanthine oxidase inhibition is maintained over 24 h; however, uric acid levels may not return to pretreatment levels until 7 to 10 days following cessation of therapy.
Indications and Usage
TabletsTreatment of primary or secondary gout, hyperuricemia resulting from chemotherapy for malignancies, recurrent calcium oxalate renal calculi.
Tablets and injectionsManagement of patients with leukemia, lymphoma, and solid tumor malignancies when concurrently receiving cancer therapy that causes elevations of serum and urinary uric acid levels. Use injection in patients who cannot tolerate oral therapy.
Unlabeled Uses
Prevention of fluorouracil-induced stomatitis and fluorouracil-induced granulocyte suppression.
Contraindications
Standard considerations.
Dosage and Administration
Control of Gout/HyperuricemiaAdults
PO 100 to 800 mg/day. For amounts over 300 mg, give divided doses.
Secondary Hyperuricemia Associated with MalignanciesChildren 6 to 10 yr of age
PO 300 mg/day.
Children under 6 yr of agePO 150 mg/day.
Prevention of Uric Acid Nephropathy in Vigorous Chemotherapy of Neoplastic DiseaseAdults
PO 600 to 800 mg/day for 2 to 3 days.
Reduction of Risk of Acute Gouty AttacksAdults (initial dose)
PO 100 mg/day, increased by 100 mg at weekly intervals until adequate response is achieved or max recommended dose (800 mg/day) is reached.
Leukemia, Lymphoma, Solid Tumor MalignanciesAdults
IV 200 to 400 mg/m 2 /day (max 600 mg/day).
ChildrenIV Starting dose 200 mg/m 2 /day.
Storage/Stability
Reconstituted solutionStore reconstituted solution at 20° to 25°C; do not refrigerate or dilute product.
TabletsStore tablets in tightly closed container in cool location.
Unreconstituted solutionStore unreconstituted powder at room temperature.
Drug Interactions
Aluminum salts, uricosuric agentsMay lessen effectiveness of allopurinol.
AmpicillinMay increase incidence of ampicillin-induced skin rash.
CyclophosphamideMay enhance bone marrow suppression.
TheophyllinesTheophylline Cl may be decreased, leading to toxicity.
Thiopurines (eg, azathioprine, mercaptopurine)Toxicity of these drugs may be increased.
Drugs that are physically incompatible in solution with allopurinol sodium for injection are the followingamikacin; amphotericin B; carmustine; cefotaxime; chlorpromazine; cimetidine; clindamycin; cytarabine; dacarbazine; daunorubicin; diphenhydramine; doxorubicin; doxycycline; droperidol; floxuridine; gentamicin; haloperidol; hydroxyzine; idarubicin; imipenem plus cilastatin; mechlorethamine; meperidine; metoclopramide; methylprednisolone sodium succinate; minocycline; nalbuphine; netilmicin; ondansetron; prochlorperazine edisylate; promethazine; sodium bicarbonate; streptozocin; tobramycin; vinorelbine tartrate.
Laboratory Test Interactions
None well documented.
Adverse Reactions
CNS
Drowsiness; generalized seizure (injectable); headache; neuritis; paresthesias; peripheral neuropathy.
Dermatologic
Allergic vasculitis; alopecia; ecchymosis; skin rash. Allergic reactions may be severe and sometimes fatal.
EENT
Epistaxis; myopathy; taste disturbance.
GI
Abdominal pain; diarrhea; dyspepsia; gastritis; granulomatous changes; nausea; vomiting.
Genitourinary
Renal failure; uremia.
Hematologic
Bone marrow depression; eosinophilia; leukocytosis; leukopenia; thrombocytopenia.
Hepatic
Cholestatic jaundice; elevated liver enzymes; hepatic necrosis; hepatitis; reversible hepatomegaly.
Other
Acute gouty attacks; arthralgia; fever; myopathy; necrotizing angiitis.
Precautions
Pregnancy
Category C .
Lactation
Excreted in breast milk.
Children
Allopurinol is rarely indicated for use in children, except for hyperuricemia resulting from malignancy or with certain rare inborn errors of purine metabolism.
Hypersensitivity
Discontinue drug at first appearance of skin rash or other signs of allergic reaction. Rash may be followed by more severe hypersensitivity reactions and, rarely, death.
Renal Function
Reduced dose is given in patients with this condition. Drug may exacerbate renal failure in certain patients.
Acute gouty attacks
May occur during initial stages of therapy.
Bone marrow depression
Reported in patients given allopurinol.
Patient Information
- Encourage patient to focus on weight loss or control.
- Tell patient to avoid purine-rich foods (eg, organ meats).
- Caution patient to avoid excessive intake of alcohol.
- Explain that gouty attacks may not end for 2 to 6 wk after beginning therapy.
- Instruct patient to stop taking medication and notify health care provider if rash or flu-like symptoms develop.
- Advise patient that drug may cause drowsiness, and to use caution while driving or performing other tasks requiring mental alertness.
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More Allopurinol resources:
Allopurinol - Includes detailed dosage instructions.
Gout, Heart Failure, Mania, Calcium Oxalate Calculi with Hyperuricosuria, Leishmaniasis, Hyperuricemia Secondary to Chemotherapy, High Risk Percutaneous Transluminal Angioplasty, Cardiothoracic Surgery, Reactive Perforating Collangenosis
