Types of medicine
What Is a Nucleoside Analogue? How These Antivirals Work
Nucleoside analogue · say it: NOO-klee-oh-side AN-uh-logAlso written: nucleoside analog, nucleoside reverse transcriptase inhibitor, NRTI, nucleotide analogue
Short answer
A nucleoside analogue is a medicine that looks like a building block of DNA or RNA, so a virus uses it by mistake and cannot copy itself properly.
What it means
Nucleosides are the building blocks that cells and viruses use to make DNA and RNA. A nucleoside analogue is a man-made look-alike. When a virus picks it up while copying its genetic material, the copying stalls. Medicines of this type are used for HIV, hepatitis B, hepatitis C, herpesviruses and some cancers.
Their labels often carry warnings about lactic acidosis and liver problems, which are rare but serious, mostly with some older drugs of this type. Hepatitis B medicines also warn that the hepatitis can flare up badly if treatment is stopped, so they should not be stopped without medical advice.
'NRTI' (nucleoside reverse transcriptase inhibitor) is the name used in HIV care for the same idea. Nucleotide analogues are very close relatives and work the same way.
Where you may see it
- The 'Description' or 'Mechanism of action' part of HIV, hepatitis B and herpes medicine labels
- Boxed warnings about lactic acidosis or hepatitis flare after stopping
- HIV and hepatitis clinic letters listing a treatment regimen
📄 How it looks on a report
Severe acute exacerbations of hepatitis B have been reported in patients who have discontinued nucleoside analogues.
🙅 What it does not mean
- It does not mean the medicine changes your own DNA.
- The warnings on the label do not mean these effects are likely for you; they list rare but important risks.
- It does not always mean the virus is removed from the body for good; often the medicine keeps the virus under control.
🎯 Check yourself
Which of these is the right meaning of “Nucleoside analogue”?
🗒️ Questions to ask your doctor
💊 Medicines whose labels mention “Nucleoside analogue”
Plain-English explanations of each medicine, from its official FDA label.
- Acyclovir
An antiviral medicine of the nucleoside analogue type, used against herpesviruses
- Lamivudine
An antiviral medicine of the nucleoside analogue reverse transcriptase inhibitor type, used here for hepatitis B
🔗 Read more from trusted sources
- “Nucleoside analogue” on MedlinePlus ↗
US National Library of Medicine
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General information about a medical word, not advice about your own results. Ask the clinician who ordered the test what it means for you.