Rheumatology Book

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AllopurinolAka: Zyloprim, Xanthine oxidase inhibitor

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  1. 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
  2. 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
  3. Mechanism: Xanthine oxidase inhibitor
    1. Inhibits Uric Acid formation
  4. Dosing
    1. Use concurrent NSAID or Colchicine when starting to prevent triggering attack
      1. Wait to start allopurinol until at least 4-6 weeks symptom-free from last attack
      2. Colchicine 0.6 mg PO daily to twice daily for 3-6 months
    2. Allopurinol 100-300 mg/day
      1. Use lowest dose to keep Uric Acid <6 mg/dl
      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): 50-100 mg daily
        5. GFR <10 ml/minute: Avoid or use with caution
  5. Monitoring: Obtain 6 weeks after starting allopurinol
    1. Complete Blood Count (CBC)
    2. Alanine Aminotransferase (ALT)
    3. Serum Creatinine
    4. Serum Uric Acid
  6. Adverse effects
    1. May precipitate acute gout attack (never start during active gout attack)
      1. See Dosing above for protocol using NSAIDs or Colchicine concurrently
    2. Hypersensitivity Syndrome (presents as dermatitis)
      1. Varies from mild rash to Stevens Johnson Syndrome
    3. Toxic Hepatitis
    4. Nausea
    5. Diarrhea
    6. Cytopenias
  7. Drug Interactions
    1. Azathioprine (toxicity)
    2. Warfarin (Allopurinal increases INR)

Allopurinol (C0002144)

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 (NCI)A drug that lowers high levels of uric acid (a byproduct of metabolism) in the blood caused by some cancer treatments.
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)
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)
ConceptsOrganic Chemical (T109) , Pharmacologic Substance (T121)
MSHD000493
English4'-HPP, ALLO, Allopurinol, Allopurinol - chemical, ALLOPURINOL PREPARATION
Spanishalopurinol, alopurinol - sustancia quimica
Parent ConceptsGout Suppressants (C0018100), Xanthine Oxidase Inhibitors (C0302609), pyrazolopyrimidine (C0597328), Purines (C0034140), Uricosuric Agents (C0041983), Duplicate concept (C1274013), Allopurinol and purine inhibitors (C1445628)
SourcesCSP, LNC, MSH, MTHSPL, NCI, NDFRT, PDQ, RXNORM, SCTSPA, SNOMEDCT, USPMG, VANDF
Derived from the NIH UMLS (Unified Medical Language System)


Zyloprim (C0701096)

ConceptsOrganic Chemical (T109) , Pharmacologic Substance (T121)
MSHD000493
EnglishAllopurinol Wellcome Brand, Glaxo Wellcome Brand of Allopurinol, Wellcome Brand of Allopurinol, Zyloprim, Zyloric
SourcesCSP, MSH, MTH, NCI, PDQ, RXNORM
Derived from the NIH UMLS (Unified Medical Language System)



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