• HIV-1 infection in adults, adolescents and children, as part of combination antiretroviral therapy
• Preferred NRTI backbone (with lamivudine) in first-line ART regimens per WHO and NACO India guidelines
• Switch therapy for patients unable to tolerate tenofovir or zidovudine-based regimens
• Component of fixed-dose combinations such as abacavir + lamivudine and abacavir + lamivudine + dolutegravir

Abacavir is intracellularly phosphorylated by cellular kinases to its active metabolite, carbovir triphosphate (CBV-TP). CBV-TP is a structural analogue of deoxyguanosine triphosphate (dGTP).

CBV-TP competes with natural dGTP for incorporation into the growing viral DNA chain by HIV-1 reverse transcriptase. Once incorporated, it terminates the chain because it lacks the 3'-hydroxyl group required for further nucleotide addition.

This blocks HIV reverse transcription, suppressing viral replication and reducing plasma HIV-1 RNA viral load. Resistance is typically associated with M184V and the K65R, L74V, Y115F mutations in reverse transcriptase.

• Adults and adolescents (≥25 kg): 600 mg once daily OR 300 mg twice daily, as part of combination ART
• Children: weight-band dosing per WHO paediatric ART guidelines; oral solution preferred for younger children
• May be taken with or without food
• Dose adjustment required in mild hepatic impairment (Child-Pugh A); contraindicated in moderate-severe hepatic impairment
• Always prescribe in combination with at least 2 other active antiretrovirals — never as monotherapy
• Dosage and duration must be decided by a qualified HIV physician based on viral load, CD4 count and treatment history

• Hypersensitivity reaction (HSR) — potentially life-threatening; risk strongly linked to HLA-B*5701 allele. Mandatory HLA-B*5701 screening before initiation is recommended
• Nausea, vomiting, diarrhoea, loss of appetite
• Headache, fatigue, insomnia
• Skin rash, fever
• Elevated liver enzymes (ALT/AST)
• Lactic acidosis with hepatic steatosis (rare, class effect of NRTIs)
• Possible increased risk of myocardial infarction in patients with underlying cardiovascular risk factors (data conflicting)

• Known hypersensitivity to abacavir or any excipient
• Patients testing positive for HLA-B*5701 allele (high risk of severe HSR)
• History of any previous abacavir-induced hypersensitivity reaction — never re-challenge
• Moderate to severe hepatic impairment (Child-Pugh B or C)
• Pregnancy and lactation — use only when clearly indicated under specialist supervision

Store below 30°C in a dry place, protected from light and moisture. Keep in original blister/bottle until use. Keep out of reach of children. Dispense strictly on a registered medical practitioner's prescription.