pharmacopeia
GET
/api/v1/drug/allopurinol

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2D structure
1,5-dihydropyrazolo[5,4-d]pyrimidin-4-one
SMILES C1=NNC2=C1C(=O)NC=N2
InChIKey OFCNXPDARWKPPY-UHFFFAOYSA-N

Mechanism of action

Sourced from openFDA

Allopurinol tablets are a structural analogue of the natural purine base, hypoxanthine. Allopurinol acts on purine catabolism, without disrupting the biosynthesis of purines.

Xanthine Oxidase

Indications

Sourced from openFDA
  • Allopurinol tablets are indicated for: The management of adults with signs and symptoms of primary or secondary gout (acute attacks, tophi, joint destruction, uric acid lithiasis, and/or nephropathy) The management of adult and pediatric patients with leukemia, lymphoma and solid tumor malignancies who are receiving cancer therapy which causes elevations of serum and urinary uric acid levels The management of adult patients with recurrent calcium oxalate calculi whose daily uric acid excretion exceeds 800 mg/day in male patients and 750 mg/day in female patients, despite lifestyle changes (such as reduction of dietary sodium, non-dairy animal protein, oxylate rich foods, refined sugars and increases in oral fluids and fruits and vegetables) Limitations of Use Allopurinol tablets are not recommended for the treatment of asymptomatic hyperuricemia.ICD-10: C85.90, C95.90, M10.9

Contraindications

Sourced from openFDA
  • Allopurinol tablets are contraindicated in patients with a history of hypersensitivity reaction to allopurinol or to any of the ingredients of allopurinol tablets. Known hypersensitivity to allopurinol or to any of the ingredients of allopurinol tablets.contraindicated

Dosage & administration

Sourced from openFDA

Gout : Prior to initiating treatment assess serum uric acid level, complete blood count, chemistry panel, liver and kidney function tests. Prophylactic treatment for gout flares is recommended. ( 2.1 , 2.2 ) Patients with normal kidney function: Initial dosage is 100 mg orally daily. Increase by 100 mg weekly increments until serum uric acid of 6 mg/dl or less is reached (maximum 800 mg daily). ( 2.3 ) Patients with impaired kidney function: The initial dosage is 50 mg orally daily. Follow recommendations for titration in patients with renal impairment until target serum uric acid level is reached. ( 2.6 ) See complete information in the Full Prescribing Information (FPI). Hyperuricemia Associated with Cancer Therapy : The recommended dosage is: Adults: 300 mg to 800 mg orally daily. Pediatric patients: 100 mg/m 2 orally every 8 hours to 12 hours (10 mg/kg/day, maximum 800 mg/day) See complete information in the FPI. ( 2.4 , 2.6 ) Recurrent Calcium Oxalate Calculi : The recommended initial dosage in patients with normal kidney function is 200 mg to 300 mg orally daily. ( 2.5 ) Dosage in Patients with Renal Impairment: See FPI for dosage modifications in patients with renal impairment.

Warnings & precautions

Sourced from openFDA

Skin Rash and Hypersensitivity: Allopurinol has been associated with serious and sometimes fatal dermatological reactions. Discontinue allopurinol tablets at the first appearance of skin rash or other signs of hypersensitivity reaction. ( 5.1 ) Gout Flares: May occur during initiation of treatment. Concurrent prophylactic treatment with colchicine or anti-inflammatory agents is recommended. ( 5.2 ) Nephrotoxicity: Allopurinol may affect kidney function. Patients with decreased kidney function require lower doses of allopurinol tablets. ( 5.3 ) Hepatoxicity: Cases of reversible hepatotoxicity have occurred. If signs and symptoms of hepatotoxicity develop, evaluate liver function. ( 5.4 ) Myelosuppression: Bone marrow suppression has been reported with allopurinol. ( 5.5 ) Potential Effect on Driving and Use of Machinery: Drowsiness, somnolence and dizziness have been reported in patients taking allopurinol tablets. ( 5.6 ) 5.1 Skin Rash and Hypersensitivity Serious and sometimes fatal dermatologic reactions, including toxic epidermal necrolysis (TEN), Stevens-Johnson syndrome (SJS), and drug reaction with eosinophilia and systemic symptoms (DRESS) have been reported in patients taking allopurinol [see Adverse Reactions ( 6 )] . These reactions occur in approximately 5 in 10,000 (0.05%) patients taking allopurinol. Other serious hypersensitivity reactions that have been reported include exfoliative, urticarial and purpuric lesions, generalized vasculitis, and irreversible hepatotoxicity.

Adverse reactions

Sourced from openFDA

The following clinically significant adverse reactions are described elsewhere in the labeling: Skin Rash and Hypersensitivity [see Warnings and Precautions ( 5.1 )] Nephrotoxicity [see Warnings and Precautions ( 5.3 )] Hepatoxicity [see Warnings and Precautions ( 5.4 )] Myelosuppression [see Warnings and Precautions ( 5.5 )] Potential Effect on Driving and Use of Machinery [see Warnings and Precautions ( 5.6 )] The following adverse reactions associated with the use of allopurinol tablets were identified in literature, unpublished clinical trials or postmarketing reports. Because some of these reactions were reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. The most frequent adverse reaction to allopurinol tablets is skin rash. Most Common Adverse Reactions (≥ 1%) Gastrointestinal : Diarrhea, nausea, alkaline phosphatase increase, AST/ALT increase. Metabolic and Nutritional : Acute attacks of gout. Skin and Appendages : Rash, maculopapular rash. Less Common Adverse Reactions (< 1%) Body As a Whole : Ecchymosis, fever, headache, malaise. Cardiovascular : Necrotizing angiitis, vasculitis, pericarditis, peripheral vascular disease, thrombophlebitis, bradycardia, vasodilation.

Use in specific populations

Sourced from openFDA

Pregnancy: May cause fetal harm. ( 8.1 ) Lactation: Advise not to breastfeed. ( 8.2 ) 8.1 Pregnancy Risk Summary Based on findings in animals, allopurinol tablets may cause fetal harm when administered to a pregnant woman. Adverse developmental outcomes have been described in exposed animals (see Data). Allopurinol and its metabolite oxypurinol have been shown to cross the placenta following administration of maternal allopurinol. Available limited published data on allopurinol use in pregnant women do not demonstrate a clear pattern or increase in frequency of adverse developmental outcomes. Among approximately 50 pregnancies described in published literature, 2 infants with major congenital malformations have been reported with following maternal allopurinol exposure. Advise pregnant women of the potential risk to a fetus. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. The background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Data Human Data Experience with allopurinol tablets during human pregnancy has been limited partly because women of reproductive age rarely require treatment with allopurinol tablets.

Pharmacokinetics

Sourced from openFDA
Metabolism
Absorption Allopurinol tablets are approximately 90% absorbed from the gastrointestinal tract. Peak plasma levels generally occur at 1.5 hours and 4.5 hours for allopurinol tablets and oxipurinol respectively.

Overdosage

Sourced from openFDA

In the management of overdosage there is no specific antidote for allopurinol tablets. Both allopurinol tablets and oxipurinol are dialyzable; however, the usefulness of hemodialysis or peritoneal dialysis in the management of an overdose of allopurinol tablets is unknown.

Approval history

Sourced from openFDA
  • Aug 19, 1966NDANDA016084Casper Pharma Llc
  • Sep 28, 1984NDANDA018832Watson Labs
  • Sep 28, 1984NDANDA018877Watson Labs
  • Oct 24, 1986ANDAANDA018659Mylan
  • Jan 9, 1987ANDAANDA071450Sun Pharm Industries
  • Apr 2, 1987ANDAANDA071587Dr Reddys
  • Apr 2, 1987ANDAANDA071586Dr Reddys
  • May 17, 1996NDANDA020298Mylan

FDA shortages

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Reference statistics from the openFDA drug-shortage dataset. For a live view, consult the FDA database directly. Not clinical guidance.

  • Allopurinol, Tablet, 100 mg (NDC 0591-5543-01)To be discontinued
    Sponsor: Teva Pharmaceuticals USA, Inc.
    Updated
  • Allopurinol, Tablet, 100 mg (NDC 0591-5543-10)To be discontinued
    Sponsor: Teva Pharmaceuticals USA, Inc.
    Updated
  • Allopurinol, Tablet, 300 mg (NDC 0591-5544-01)To be discontinued
    Sponsor: Teva Pharmaceuticals USA, Inc.
    Updated
  • Allopurinol, Tablet, 300 mg (NDC 0591-5544-05)To be discontinued
    Sponsor: Teva Pharmaceuticals USA, Inc.
    Updated

FAERS reports

View JSON
Reference statistics only. FAERS reports are voluntarily submitted and are not incidence rates, safety signals, or causal evidence. Counts reflect reporting volume — how often a reaction was reported, not how often it occurs. For decision-grade use, consult openFDA and the FAERS Public Dashboard directly.
153,755 total reports matchedLatest report Share = reports listing the reaction ÷ total matched reports. Rows can sum to >100% because a single report often lists multiple reactions.
  1. 1Diarrhoea8,5915.6%
  2. 2Fatigue8,1415.3%
  3. 3Dyspnoea7,8295.1%
  4. 4Nausea7,1944.7%
  5. 5Death6,8044.4%
  6. 6Acute Kidney Injury6,6384.3%
  7. 7Off Label Use6,4914.2%
  8. 8Pyrexia6,0513.9%
  9. 9Pneumonia5,6583.7%
  10. 10Asthenia5,5913.6%
  11. 11Anaemia5,3823.5%
  12. 12Drug Ineffective5,0613.3%
  13. 13Dizziness5,0433.3%
  14. 14Renal Failure4,7303.1%
  15. 15Fall4,5983.0%

Literature

View JSON

Recent PubMed references pinned to Allopurinol as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

Clinical trials

View JSON

The 10 most recently updated of 224 ClinicalTrials.gov registrations naming Allopurinol as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

Pharmacogenomics

View JSON

CPIC-curated drug–gene pairs for Allopurinol. Levels describe the strength of curated evidence and guideline status — never a recommendation to test or to adjust therapy.

  • HLA-ACPIC B/C (provisional)ClinPGx 2B
  • HLA-BCPIC AClinPGx 1AFDA label: Testing Recommended
    HLA-B and Allopurinol
  • HLA-CCPIC C (provisional)ClinPGx 2B

Frequently asked questions

How does Allopurinol work?
Allopurinol tablets are a structural analogue of the natural purine base, hypoxanthine. Allopurinol acts on purine catabolism, without disrupting the biosynthesis of purines.
What is Allopurinol used for?
According to FDA labeling, Allopurinol carries indications including: Allopurinol tablets are indicated for: The management of adults with signs and symptoms of primary or secondary gout (acute attacks, tophi, joint destruction, uric acid lithiasis, and/or nephropathy) The management of adult and pediatric patients with leukemia, lymphoma and solid tumor malignancies who are receiving cancer therapy which causes elevations of serum and urinary uric acid levels The management of adult patients with recurrent calcium oxalate calculi whose daily uric acid excretion exceeds 800 mg/day in male patients and 750 mg/day in female patients, despite lifestyle changes (such as reduction of dietary sodium, non-dairy animal protein, oxylate rich foods, refined sugars and increases in oral fluids and fruits and vegetables) Limitations of Use Allopurinol tablets are not recommended for the treatment of asymptomatic hyperuricemia.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.
What class of drug is Allopurinol?
Allopurinol is classified as Preparations inhibiting uric acid production, Xanthine Oxidase Inhibitor, Xanthine Oxidase Inhibitors, Decreased Uric Acid Synthesis.
What are the brand names for Allopurinol?
Allopurinol is marketed under brand names including Aloprim, Zyloprim.
What are the contraindications for Allopurinol?
Allopurinol labeling lists contraindications including: Allopurinol tablets are contraindicated in patients with a history of hypersensitivity reaction to allopurinol or to any of the ingredients of allopurinol tablets. Known hypersensitivity to allopurinol or to any of the ingredients of allopurinol tablets.. Always consult the full prescribing information and a clinician.
Note. Data for allopurinol is illustrative MVP content compiled from public sources. pharmacopeia is for educational and informational use only and is not a substitute for professional medical advice.

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