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Abacavir

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Abacavir, Ziagen

  • See Also
  1. Anti-Retroviral Therapy
  2. Nucleoside Reverse Transcriptase Inhibitor
  • Indications
  1. HIV Infection (combination protocols)
  • Contraindications
  1. Moderate to severe Cirrhosis (Child-Pugh Score >6)
  2. HLA-B*5701 positive state (screen in advance of starting)
    1. Associated with life-threatening Hypersensitivity
  • Mechanism
  1. Nucleoside Reverse Transcriptase Inhibitor
  • Precautions
  1. Do not use unless patient is negative for HLA-B5701
    1. Risk of Hypersensitivity Reaction if HLA-B5701 positive
    2. Lucas (2007) J Antimicrob Chemother 59(4):591-3 +PMID:17317695 [PubMed]
  • Dosing
  1. Used in combination with other Retroviral agents
  2. Adult (or child weight >25 kg)
    1. Abacavir 300 mg orally twice daily
  3. Adult Hepatic Dosing in Mild Cirrhosis (Child-Pugh Score 5 to 6)
    1. Avoid Abacavir in moderate to severe Cirrhosis (Child-Pugh Score >6)
    2. Decrease dose to 200 mg orally twice daily (using 10 ml twice daily of oral solution)
  4. Child with Abacavir tablets
    1. Weight 14 to 20 kg: 150 mg orally twice daily OR 300 mg orally once daily
    2. Weight 20 to 25 kg: 150 mg qAM and 300 mg qPM orally OR 450 mg orally once daily
    3. Weight >25 kg: 300 mg orally twice daily OR 600 mg orally once daily (adult dose)
  5. Child with Abacavir oral solution (20 mg/ml, age >=3 months)
    1. Give 8 mg/kg (max 300 mg) orally twice daily OR
    2. Give 16 mg/kg (max 600 mg) orally once daily
  • Adverse Effects
  1. Hypersensitivity (3%)
    1. Presents with Fever and Rash
    2. Associated with HLA-B*5701 positive state
    3. Mean onset 11 days after start
    4. Lethal reaction if restarted after reaction (50%)
    5. Never rechallenge Abacavir after reaction
  2. Cardiovascular Risk
    1. Unclear association with Myocardial Infarction
  3. Class Effects (with all nRTIs)
    1. Lactic Acidosis
    2. Hepatic Steatosis
  • Safety
  1. Avoid in Lactation
  2. Pregnancy
    1. Considered among the preferred nRTIs in pregnancy
  • Resources
  1. Abacavir (DailyMed)
    1. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=5676d391-f9a4-44be-9604-954b3d8d0e2b
  2. Abacavir Hypersensitivity Registry
    1. https://www.ncbi.nlm.nih.gov/gtr/conditions/C1840547/
  • References
  1. (1998) Med Lett Drugs Ther 40(1041):115 [PubMed]
  2. (2009) Treat Guidel Med Lett 7(78): 11-22 [PubMed]
  3. Reust (2011) Am Fam Physician 83(12): 1443-51 [PubMed]