II. Indications

  1. Gout Prophylaxis
    1. Uric Acid over-producers (Uric Acid > 750 mg/24h)
    2. Used in Uric Acid under-excreters as well
  2. Criteria
    1. Recurrent episode of gout (>3 attacks per year)
    2. Tophaceous gout
    3. Nephrolithiasis

III. Precautions

  1. Avoid in acute gout attack (wait at least 4-6 weeks after acute attack)
  2. Avoid use with Azathioprine (causes toxic levels)
  3. Avoid in Renal Failure (or use low dose)
  4. Do not use for asymptomatic Hyperuricemia

IV. Mechanism

  1. Xanthine Oxidase Inhibitor
  2. Inhibits Uric Acid formation

V. Dosing

  1. Use concurrent antiinflammatory agent when starting to prevent triggering attack
    1. Wait to start Allopurinol until at least 6-8 weeks symptom-free from last attack
    2. Antiinflammatory agent options to start concurrently with Allopurinol (continue for first 3-6 months)
      1. NSAIDS (avoid in Chronic Kidney Disease, heart disease or liver disease)
        1. Aleve 220 mg (OTC) orally twice daily or
        2. Naprosyn 250 mg orally twice daily or
        3. Indomethacin 25 mg orally twice daily
      2. Prednisone (if NSAIDs contraindicated)
        1. Maintenance: 10 mg orally daily, then 5 mg orally daily for 3-6 months
        2. Acute Exacerbation (start at first symptoms of gout recurrence): 40 mg orally for 1-3 days
          1. Have available as emergency prescription
      3. Colchicine
        1. Colchicine was a first line agent for Allopurinol initiation (but now too expensive)
          1. Generic preparations were removed from market
        2. Colchicine 0.6 mg PO daily to twice daily
  2. Allopurinol 100-300 mg/day
    1. Use lowest dose to keep Uric Acid <6 mg/dl (<5 mg/dl if symptomatic)
      1. Probenacid may be used in combination with Allopurinol if GFR>50 ml/min and normal Urine Uric Acid normal
      2. Duzallo (Allopurinol with Lesinurad) is an expensive alternative to Probenacid and Allopurinol
    2. Initiating dose
      1. Start: 100 mg daily for 2 weeks
      2. Next: 200 mg daily for 2 weeks
      3. Next: 300 mg daily (most effective dose for most patients)
      4. Some patients require higher doses (up to 800 mg/day) to maintain Uric Acid <6 mg/dl
    3. Adjust for Renal Function
      1. GFR >90 ml/min: 300 mg daily
      2. GFR 60-89 ml/min: 200 mg daily
      3. GFR 30-59 ml/min: 100 mg daily
      4. GFR 10-29 ml/min (or Cr >1.5): 50 mg daily
      5. GFR <10 ml/minute: Avoid or use with caution

VI. Monitoring: Obtain 6 weeks after starting Allopurinol

VII. Adverse effects (more common with renal dysfunction)

  1. May precipitate acute gout attack (never start during active gout attack)
    1. See Dosing above for protocol using NSAIDs or Colchicine concurrently
  2. Severe Hypersensitivity Syndrome (presents as dermatitis)
    1. Varies from mild rash to Stevens Johnson Syndrome
    2. Genetic testing (HLA B5801) prior to use if Hans Chinese, Thai or if CKD 3, Korean
    3. Stop Allopurinol if this occurs
  3. Toxic Hepatitis
  4. Nausea
  5. Diarrhea
  6. Cytopenias

VIII. Drug Interactions

  1. Azathioprine (toxicity)
  2. Warfarin (Allopurinal increases INR)

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Cost: Medications

Allopurinol (on 6/18/2017 at Walmart.com)
Allopurinol 100mg #30 tablets for $4.00 $0.13 each
Allopurinol 100mg #90 tablets for $10.00 $0.11 each
Allopurinol 300mg #30 tablets for $4.00 $0.13 each
Allopurinol 300mg #90 tablets for $10.00 $0.11 each
allopurinol (on 5/17/2017 at Medicaid.Gov Survey of pharmacy drug pricing)
ALLOPURINOL 100 MG TABLET Generic $0.13 each
ALLOPURINOL 300 MG TABLET Generic $0.24 each

Ontology: Allopurinol (C0002144)

Definition (CHV) a kind of gout treatment drug
Definition (NCI) A structural isomer of hypoxanthine. Allopurinol inhibits xanthine oxidase, an enzyme that converts oxypurines to uric acid. By blocking the production of uric acid, this agent decreases serum and urine concentrations of uric acid, thereby providing protection against uric acid-mediated end organ damage in conditions associated with excessive production of uric acid, i.e. the massive cell lysis associated with the treatment of some malignancies. (NCI04)
Definition (NCI_NCI-GLOSS) A drug that lowers high levels of uric acid (a byproduct of metabolism) in the blood caused by some cancer treatments.
Definition (MSH) A XANTHINE OXIDASE inhibitor that decreases URIC ACID production. It also acts as an antimetabolite on some simpler organisms.
Definition (CSP) drug used to treat gout and other conditions in which there is an excessive buildup of uric acid.
Definition (PDQ) A structural isomer of hypoxanthine. Allopurinol inhibits xanthine oxidase, an enzyme that converts oxypurines to uric acid. By blocking the production of uric acid, this agent decreases serum and urine concentrations of uric acid, thereby providing protection against uric acid-mediated end organ damage in conditions associated with excessive production of uric acid, i.e. the massive cell lysis associated with the treatment of some malignancies. Check for "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=38452&idtype=1" active clinical trials or "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=38452&idtype=1&closed=1" closed clinical trials using this agent. ("http://nciterms.nci.nih.gov:80/NCIBrowser/ConceptReport.jsp?dictionary=NCI_Thesaurus&code=C224" NCI Thesaurus)
Concepts Pharmacologic Substance (T121) , Organic Chemical (T109)
MSH D000493
SnomedCT 391735003, 387135004, 25246002
LNC LP17988-4, MTHU024809
English Allopurinol, 4H-Pyrazolo(3,4-d)pyrimidin-4-one, 1,5-dihydro-, 1H-Pyrazolo[3,4-d]pyrimidin-4-ol, 4-Hydroxypyrazolo[3,4-d]pyrimidine, 1,5-Dihydro-4H-pyrazolo[3,4-d]pryimidin-4-one, allopurinol, 4'-HPP, allopurinol (medication), ALLOPURINOL, Allopurinol [Chemical/Ingredient], allopurinol sodium (as allopurinol), Allopurinol - chemical (substance), Allopurinol - chemical, 1,5-Dihydro-4H-pyrazolo[3,4-d]pyrimidin-4-one, Allopurinol (product), Allopurinol (substance), ALLO
Swedish Allopurinol
Czech alopurinol
Finnish Allopurinoli
Russian ALLOPURINOL, АЛЛОПУРИНОЛ
Japanese アロプリノール
Croatian ALOPURINOL
Polish Allopurinol, Zyloprin
Spanish alopurinol - sustancia química (sustancia), alopurinol - sustancia química, alopurinol (producto), alopurinol (sustancia), alopurinol, Alopurinol
French Allopurinol
German Allopurinol
Italian Allopurinolo
Portuguese Alopurinol

Ontology: Zyloprim (C0701096)

Concepts Pharmacologic Substance (T121) , Organic Chemical (T109)
MSH D000493
English zyloric, zyloprim, Zyloric, Glaxo Wellcome Brand of Allopurinol, Wellcome Brand of Allopurinol, Allopurinol Wellcome Brand, Zyloprim