Adult: Combined w/ other antiretrovirals: 300 mg bid or 600 mg once daily. Child: ≥3 mth 14 to <20 kg: 150 mg bid or 300 mg once daily; ≥20 kg to <25 kg: 150 mg in the morning and 300 mg in the evening or 450 mg once daily; ≥25 kg: Same as adult dose.
Special Patient Group
Human leukocyte antigen B (HLA-B) plays a critical role in immune recognition of pathogens. A variant allele HLA-B*57:01 is associated with increased risk of life-threatening hypersensitivity reactions to abacavir. The prevalence of this variant allele is estimated in 11% of Southwest Asians, 6.8 % of Europeans, 2.6% of South Americans, 2.5% of Middle Easterners, 2.2% of Mexicans, 1.6% of Asians, and 1% of Africans.
Patients who are positive to HLA-B*57:01 allele have higher risk of developing hypersensitivity reactions with abacavir. CPIC does not recommend use of abacavir for these patients. Genetic screening is recommended prior to initiation of treatment. However, a negative test result for HLA-B*57:01 does not absolutely rule out the possibility of developing hypersensitivity reactions.
Decreased serum concentrations of methadone. Slightly decreased plasma concentration w/ potent enzymatic inducers (e.g. rifampicin, phenobarbital, phenytoin). Ribavirin may enhance the hepatotoxic effect of nucleoside reverse transcriptase inhibitors.
Description: Abacavir competitively inhibits the reverse transcriptase of retroviruses, interfering w/ HIV viral RNA-dependent DNA polymerase resulting in inhibition of viral replication. Pharmacokinetics: Absorption: Rapidly absorbed from the GI tract. Absorption slightly delayed by food. Bioavailability: Approx 80%. Time to peak plasma concentration: 0.7-1.7 hr. Distribution: Distributed into CSF. Crosses the placenta and blood brain barrier. Volume of distribution: 0.86 ± 0.15 L/kg. Plasma protein binding: Approx 50%. Metabolism: Undergoes intracellular metabolism to carbovir triphosphate (active metabolite); hepatic metabolism via alcohol dehydrogenase and glucuronidation to inactive carboxylate and glucuronide metabolites. Excretion: Mainly via urine. Elimination half-life: About 1.5 hr.
Store between 20-25°C. Oral soln may be refrigerated, do not freeze.
J05AF06 - abacavir ; Belongs to the class of nucleoside and nucleotide reverse transcriptase inhibitors. Used in the systemic treatment of viral infections.
Dean, L. Abacavir Therapy and HLA-B*57:01 Genotype. Medical Genetics Summaries [Internet]. Bethesda (MD): National Center for Biotechnology Information (US). Accessed 11/09/2018. PMID: 28520363Martin M, Hoffman J, Freimuth et al. Clinical Pharmacogenetics Implementation Consortium (CPIC) Guidelines for HLA-B Genotype and Abacavir Dosing: 2014 Update. Clinical Pharmacogenetics Implementation Consortium. Accessed 17/10/2018Martin MA, Klein TE, Dong BJ, et al. Clinical Pharmacogenetics Implementation Consortium Guidelines for HLA-B Genotype and Abacavir Dosing. Nature Publishing Group. 91. doi: 10.1038/clpt.2011.355. Accessed 17/10/2018Abacavir Overview. Pharmacogenomics Knowledgebase (PharmGKB). https://www.pharmgkb.org/. Accessed 11/09/2018.Abacavir Sulfate Tablet, Film Coated (Apotex Corp). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 18/08/2016.Anon. Abacavir. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 15/02/2016.Buckingham R (ed). Abacavir. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 15/02/2016.Clinical Pharmacogenetics Implementation Consortium Guidelines for HLA-B Genotype and Abacavir Dosing. Clinical Pharmacogenetics Implementation Consortium (CPIC). https://cpicpgx.org/. Accessed 17/10/2018.Joint Formulary Committee. Abacavir. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. Accessed 15/02/2016.McEvoy GK, Snow EK, Miller J et al (eds). Abacavir Sulfate. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 15/02/2016.Supplemental Material CPIC Guidelines for HLA-B Genotype and Abacavir Dosing: 2014 Update. Clinical Pharmacogenetics Implementation Consortium (CPIC). https://cpicpgx.org/. Accessed 17/10/2018.