Zidovudine with lamivudine

How it works

Both components are phosphorylated intracellularly to active triphosphates that competitively inhibit HIV reverse transcriptase and act as chain terminators, blocking viral DNA synthesis.

Prescribing in practice

• Zidovudine commonly causes bone-marrow suppression (anaemia and neutropenia), so the full blood count must be monitored; both drugs carry a class risk of lactic acidosis and hepatomegaly with steatosis.
• It must always be used as part of a fully suppressive combination regimen, never as monotherapy, to avoid resistance.
• Lamivudine is also active against hepatitis B, so stopping therapy may precipitate a hepatitis flare in co-infected patients.

Monitoring

Monitor full blood count (particularly during early zidovudine therapy), liver function and HIV viral load and CD4 count.

Counselling the patient

• Take every dose to keep the virus suppressed and prevent resistance.
• Report unusual tiredness, breathlessness or pale skin which may indicate anaemia.
• Seek urgent advice for severe nausea, abdominal pain or rapid deep breathing.

Evidence & guidelines

Zidovudine plus lamivudine is a long-established NRTI backbone, though newer regimens are now generally preferred in UK HIV guidelines.