Abacavirlamivudine

Abacavirlamivudine is a fixed-dose combination antiretroviral medication used in the treatment of HIV-1 infection. The tablet combines abacavir and lamivudine, two nucleoside reverse transcriptase inhibitors (NRTIs), and is marketed under names such as Epzicom in the United States and Kivexa in parts of Europe. It is prescribed as part of combination antiretroviral therapy (cART) with other agents and is not intended for use as monotherapy.

Mechanism of action: Both components inhibit HIV-1 reverse transcriptase, an enzyme required for viral DNA synthesis. By blocking this enzyme, abacavir and lamivudine cause chain termination during viral replication, reducing viral load when used as part of a multi-drug regimen.

Clinical use: The fixed-dose tablet is indicated for the treatment of HIV-1 infection in adults and certain pediatric patients as part of cART. The choice of regimen depends on resistance testing, prior treatment history, and concomitant medications. It is used in various first-line regimens or as a switch option when appropriate components are selected.

Dosing and administration: The standard tablet provides 600 mg abacavir and 300 mg lamivudine and is taken once daily, with or without food, as directed by a clinician. Dosing may be adjusted or avoided in some cases of renal impairment; follow the prescribing clinician’s guidance. Before starting abacavir-containing therapy, patients are screened for the HLA-B*57:01 allele due to the risk of hypersensitivity reactions.

Safety and adverse effects: Common adverse effects include headache, nausea, diarrhea, fatigue, and rash. Serious adverse events include hypersensitivity reactions and, rarely, lactic acidosis with hepatomegaly. Some studies have suggested a potential association between abacavir and cardiovascular risk, so caution is advised in patients with cardiovascular risk factors.

Pregnancy considerations: ABC/3TC can be used during pregnancy if clinically indicated, with monitoring, and lamivudine provides activity against hepatitis B in coinfected individuals.