Last reviewed 2026-04-20 · How we verify

Ziagen (ABACAVIR)

Abacavir works by mimicking a building block of DNA, tricking the virus into incorporating it into its genetic material and preventing replication.

Ziagen (Abacavir) is a small molecule nucleoside analog reverse transcriptase inhibitor developed by ViiV Healthcare, targeting the treatment of human immunodeficiency virus (HIV) infection. It was first approved by the FDA in 1998 and is now off-patent with multiple generic manufacturers. As a nucleoside analog, Abacavir works by inhibiting the reverse transcriptase enzyme, which is essential for viral replication. Key safety considerations include hypersensitivity reactions and mitochondrial toxicity. Commercially, Ziagen is available as a generic medication.

At a glance

Mechanism of action

Mechanism of Action:. Abacavir is carbocyclic synthetic nucleoside analogue. Abacavir is converted by cellular enzymes to the active metabolite, carbovir triphosphate (CBV-TP), an analogue of deoxyguanosine-5-triphosphate (dGTP). CBV-TP inhibits the activity of HIV-1 reverse transcriptase (RT) both by competing with the natural substrate dGTP and by its incorporation into viral DNA. The lack of 3-OH group in the incorporated nucleotide analogue prevents the formation of the to phosphodiester linkage essential for DNA chain elongation, and therefore, the viral DNA growth is terminated. CBV-TP is weak inhibitor of cellular DNA polymerases , and Lamivudine is synthetic nucleoside analogue. Intracellularly lamivudine is phosphorylated to its active 5-triphosphate metabolite, lamivudine triphosphate (3TC-TP). The principal mode of action of 3TC-TP is inhibition of RT via DNA chain termination after incorporation of the nucleotide analogue. CBV-TP and 3TC-TP are weak inhibitors of cellular D

Approved indications

• Human immunodeficiency virus infection

Boxed warnings

• WARNING: HYPERSENSITIVITY REACTIONS Serious and sometimes fatal hypersensitivity reactions, with multiple organ involvement, have occurred with abacavir. Patients who carry the HLA-B*5701 allele are at a higher risk of a hypersensitivity reaction to abacavir; although, hypersensitivity reactions have occurred in patients who do not carry the HLA-B*5701 allele [see Warnings and Precautions (5.1) ]. Abacavir is contraindicated in patients with a prior hypersensitivity reaction to abacavir and in HLA-B*5701-positive patients [see Contraindications (4) , Warnings and Precautions (5.1) ]. All patients should be screened for the HLA-B*5701 allele prior to initiating therapy with abacavir or reinitiation of therapy with abacavir, unless patients have a previously documented HLA-B*5701 allele assessment. Discontinue abacavir immediately if a hypersensitivity reaction is suspected, regardless of HLA-B*5701 status and even when other diagnoses are possible [see Contraindications (4) , Warnings and Precautions (5.1) ]. Following a hypersensitivity reaction to abacavir, NEVER restart abacavir or any other abacavir-containing product because more severe symptoms, including death can occur within hours. Similar severe reactions have also occurred rarely following the reintroduction of abacavir-containing products in patients who have no history of abacavir hypersensitivity [see Warnings and Precautions (5.1) ]. WARNING: HYPERSENSITIVITY REACTIONS See full prescribing information for complete boxed warning. Serious and sometimes fatal hypersensitivity reactions have occurred with abacavir. (5.1) Hypersensitivity to abacavir is a multi-organ clinical syndrome. (5.1) Patients who carry the HLA-B*5701 allele are at a higher risk of experiencing a hypersensitivity reaction to abacavir. (5.1) Abacavir is contraindicated in patients with a prior hypersensitivity reaction to abacavir and in HLA-B*5701-positive patients. (4) Discontinue abacavir as soon as a hypersensitivity reaction is suspected. Regardless of HLA-B*5701 status, permanently discontinue abacavir if hypersensitivity cannot be ruled out, even when other diagnoses are possible. (5.1) Following a hypersensitivity reaction to abacavir, NEVER restart abacavir or any other abacavir-containing product. (5.1)

Common side effects

• Dreams/sleep disorders
• Nausea
• Headache
• Malaise and fatigue
• Nausea and vomiting
• Hypersensitivity reaction
• Diarrhea
• Rashes
• Abdominal pain/gastritis/gastrointestinal signs and symptoms
• Depressive disorders
• Dizziness
• Musculoskeletal pain

Key clinical trials

• Study of Cobicistat-Boosted Atazanavir (ATV/co), Cobicistat-Boosted Darunavir (DRV/co) and Emtricitabine/Tenofovir Alafenamide (F/TAF) in Children With HIV (PHASE2,PHASE3)
• Study to Evaluate the Efficacy, Safety, and Tolerability of Long-acting Intramuscular Cabotegravir and Rilpivirine for Maintenance of Virologic Suppression Following Switch From an Integrase Inhibitor in HIV-1 Infected Therapy Naive Participants (PHASE3)
• Moving on After Breast Cancer Trial for Depressed Breast Cancer Survivors in Pakistan (NA)
• A Study to Provide Continued Access to Study Drug to Children and Adolescents Who Have Completed Clinical Studies Involving Gilead HIV Treatments (PHASE4)
• Study of GS-3242 in Participants With HIV-1; Substudy-05 (PHASE1)
• Dolutegravir Study in HIV-1 Participants Completing IMPAACT Studies P1093 and P2019 (PHASE3)
• Pharmacokinetic Study of Antiretroviral Drugs and Related Drugs During and After Pregnancy
• Study to Compare an Oral Weekly Islatravir/Lenacapavir Regimen With Standard of Care in Virologically Suppressed People With HIV-1 (PHASE3)

Primary sources

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Competitive intelligence

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