Dual NRTI backbone Pregnancy: eMC §4.6: in pregnant women treated with abacavir, more than 800 first-trimester and more than 1000 second/third-trimester outcomes indicate no malformative or foetal/neonatal effect; for lamivudine, more than 1000 outcomes in each period indicate the same. There are no data on the fixed combination in pregnancy, but the malformative risk is considered unlikely in humans on those data. Animal studies showed embryo/foetal toxicity with abacavir in rats (not rabbits) and increased early embryonic deaths with lamivudine in rabbits (not rats). In hepatitis co-infected patients treated with a lamivudine-containing product who become pregnant, consider the possibility of recurrence of hepatitis if lamivudine is stopped. Breast-feeding is not recommended for women living with HIV in order to avoid transmission of HIV.

Abacavir with lamivudine

Brand names: Kivexa

A fixed-dose dual nucleoside reverse transcriptase inhibitor tablet combining abacavir and lamivudine, used as the backbone of combination antiretroviral therapy for HIV-1 infection alongside a third agent.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: One tablet (abacavir 600 mg / lamivudine 300 mg) once daily

Route: Oral - can be taken with or without food

Frequency: Once daily

eMC §4.2 (Abacavir/Lamivudine 600 mg/300 mg film-coated tablets). Therapy should be prescribed by a physician experienced in the management of HIV infection. The recommended dose is one tablet once daily for adults, adolescents and children weighing at least 25 kg. It must NOT be given to children weighing less than 25 kg because it is a fixed-dose tablet that cannot be dose reduced, and it should not be prescribed for patients requiring dose adjustments - separate preparations of abacavir or lamivudine are available where discontinuation or dose adjustment of one component is indicated. HLA-B*5701 (SPC §4.4): HLA-B*5701 status must always be documented before starting; never initiate in a patient with positive HLA-B*5701 status, nor in a patient with negative status who had a suspected abacavir hypersensitivity reaction on a previous abacavir-containing regimen (e.g. abacavir, abacavir/lamivudine/zidovudine, abacavir/dolutegravir/lamivudine). Stop without delay if a hypersensitivity reaction is suspected, even in the absence of the allele, and never re-initiate any abacavir-containing product afterwards - restarting can cause a prompt, more severe reaction within hours including life-threatening hypotension and death; instruct patients who have had a suspected reaction to dispose of their remaining tablets. Symptoms of abacavir hypersensitivity usually appear within the first six weeks (median time to onset 11 days) and almost always include fever and/or rash. ELDERLY: no pharmacokinetic data in patients over 65 years; special care is advised because of age-related decline in renal function and altered haematological parameters. HEPATIC IMPAIRMENT: abacavir is primarily metabolised by the liver; no clinical data in moderate or severe hepatic impairment, so use is not recommended unless judged necessary. In mild hepatic impairment (Child-Pugh 5-6) close monitoring is required, including abacavir plasma levels if feasible. PAEDIATRIC: safety and efficacy in children weighing less than 25 kg has not been established and no posology recommendation can be made - verify any under-18 use against a children's formulary.

Dose adjustments

Renal

eMC §4.2: not recommended for use in patients with a creatinine clearance below 30 mL/min. No dose adjustment is required in mild or moderate renal impairment, but lamivudine exposure is significantly increased at a creatinine clearance below 50 mL/min.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substances or to any of the excipients (eMC §4.3)
eMC §4.4 also directs that this product must never be initiated in a patient with a positive HLA-B*5701 status, or in an HLA-B*5701-negative patient who had a suspected abacavir hypersensitivity reaction on a previous abacavir-containing regimen; the US abacavir labelling lists presence of the HLA-B*5701 allele, prior hypersensitivity reaction to abacavir, and moderate or severe hepatic impairment as contraindications

Side effects

Nausea, vomiting and diarrhoea (common, both components); abdominal pain or cramps with lamivudine
Headache (common, both components); insomnia (common, lamivudine)
Hypersensitivity (common, abacavir) - many listed reactions (nausea, vomiting, diarrhoea, fever, lethargy, rash) also occur in abacavir hypersensitivity, so patients with these symptoms must be carefully evaluated
Rash without systemic symptoms (common, abacavir); rash and alopecia (common, lamivudine)
Fever, lethargy, fatigue and malaise (common); anorexia (common, abacavir); cough and nasal symptoms (common, abacavir)
Uncommon: neutropenia and anaemia (both occasionally severe), thrombocytopenia, transient rises in liver enzymes. Rare: pancreatitis, hepatitis, rhabdomyolysis, angioedema. Very rare: lactic acidosis, pure red cell aplasia, erythema multiforme, Stevens-Johnson syndrome and toxic epidermal necrolysis, peripheral neuropathy/paraesthesia

Interactions

Methadone (US abacavir labelling §7.1) - oral methadone clearance increased; an increased methadone dose may be required in a small number of patients
Riociguat (US labelling §7.2) - co-administration with a fixed-dose abacavir-containing combination increased riociguat exposure; the riociguat dose may need to be reduced
The eMC §4.5 interaction section was not captured in this bundle - clinician to review it in the SPC

Clinical monograph

How it works

Both components are nucleoside analogues that, after intracellular phosphorylation, are incorporated into viral DNA by reverse transcriptase and cause chain termination, suppressing HIV replication.

Prescribing in practice

Test for HLA-B*57:01 before initiation and do not use in carriers or anyone with previous abacavir hypersensitivity, given the risk of a severe and potentially fatal reaction on re-exposure.
Avoid this fixed-dose product where lamivudine requires dose reduction, such as in significant renal impairment, and prescribe the individual components instead.
An appropriate third active antiretroviral agent must always be co-prescribed, as this combination alone does not constitute a complete regimen.

Monitoring

Monitor HIV viral load, CD4 count and renal function, and review for any signs of hypersensitivity, particularly in the first weeks.

Counselling the patient

Keep your hypersensitivity alert card with you and seek urgent advice if you develop fever or rash.
Never restart abacavir after a suspected reaction unless specifically advised by the HIV team.
Take the tablet regularly to maintain viral suppression and reduce resistance.

Evidence & guidelines

MHRA guidance mandates HLA-B*57:01 screening before abacavir use, and this nucleoside backbone is well established within combination antiretroviral therapy in UK HIV treatment guidelines.

Reference: BHIVA 2022; SmPC Kivexa; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways