Abacavir is a nucleoside analogue reverse transcriptase inhibitor (NRTI) used in HIV treatment. It is important to note the risk of hypersensitivity reaction, which can be fatal if the drug is not discontinued immediately.
Also known as: Ziagen, ABC
Abacavir and lamivudine are frequently combined in first-line regimens (2 NRTIs). There is no clinically significant adverse interaction.
Abacavir and lamivudine are frequently combined as the NRTI backbone in first-line HIV regimens (e.g. ABC + 3TC + DTG, or ABC + 3TC + EFV). Both act as nucleoside/nucleotide reverse transcriptase analogues, but do not significantly compete for the same metabolic pathways — abacavir is metabolised by alcohol dehydrogenase and UGT1A1, while lamivudine is excreted essentially unchanged renally. The combination is synergistic and well tolerated, with a complementary side effect profile. The standard dose is abacavir 600 mg + lamivudine 300 mg, once daily (fixed-dose combination available). The only prerequisite is HLA-B*571 testing before starting abacavir.
Abacavir + lamivudine: intentional first-line combination (2 NRTIs). No adverse interaction — therapeutic synergy.
Both act as nucleoside/nucleotide reverse transcriptase analogues, but do not significantly compete for the same metabolic pathways. The combination is synergistic and well tolerated.
Assess HLA-B*5701 before starting abacavir. Monitor renal function.
None.
No restrictions. Standard dose: abacavir 600 mg + lamivudine 300 mg, once daily.
DailyMed/FDA (NIH/NLM) — approved Abacavir (Ziagen) label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=ca73b519-015a-436d-aa3c-af53492825a1 ; approved Lamivudine label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=cb340b00-f2a8-48e7-af4b-07b3d6a1f5c3
Food does not significantly affect abacavir absorption.
Can be taken with or without food.
DailyMed/FDA (NIH/NLM) — approved Abacavir (Ziagen) label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=ca73b519-015a-436d-aa3c-af53492825a1
HLA-B*5701-positive patients are at high risk of abacavir hypersensitivity reaction, which can be fatal.
MANDATORY HLA-B*5701 testing before initiation. If positive, CONTRAINDICATED. Discontinue IMMEDIATELY if hypersensitivity suspected.
DailyMed/FDA (NIH/NLM) — approved Abacavir (Ziagen) label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=ca73b519-015a-436d-aa3c-af53492825a1
Animal studies did not demonstrate teratogenicity. Limited human data. Can be used when indicated.
Can be used in all trimesters when indicated.
Excreted in breast milk. Artificial feeding is recommended for HIV-positive mothers.
Reliable contraceptive methods are recommended.
DailyMed/FDA (NIH/NLM) — approved Abacavir (Ziagen) label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=ca73b519-015a-436d-aa3c-af53492825a1
Clinical and educational support tool. The information does not replace a medical prescription or the opinion of a qualified healthcare professional.
Abacavir is a guanosine nucleoside analogue that inhibits HIV-1 reverse transcriptase, after intracellular activation to the active triphosphate.
Intracellularly phosphorylated to the active triphosphate (carbovir triphosphate), which incorporates into viral DNA and causes chain termination. Does not require initial phosphorylation by cellular kinases (unlike other NRTIs).
Oral bioavailability: 83%. Tmax: 1-1.5 hours. Food does not significantly affect absorption. Can be taken with or without food.
Metabolised by alcohol dehydrogenase and UGT1A1 to the carboxylate metabolite (major metabolite, 66% in urine). Oxidative metabolism by CYP3A4 is secondary.
1.5-2 hours. Elimination: ~66% urine (metabolites), ~12% faeces. No dose adjustment required in mild-moderate renal impairment.
Medicines from the same therapeutic group (ATC classification) or the same pharmacological class.
