Types of medicine
What Is an Antiviral? How It Works and Label Warnings
Antiviral · say it: AN-tee-VY-rulAlso written: antiviral medicine, antiviral drug, antivirals
Short answer
An antiviral is a medicine that works against viruses, stopping them from multiplying. Different antivirals work against different viruses.
What it means
Antivirals are medicines that interfere with a virus's ability to enter cells or copy itself. Each one usually works only against particular viruses. Examples include medicines for flu (such as oseltamivir), herpes and shingles (acyclovir, valacyclovir), HIV (antiretrovirals), hepatitis B and C, and COVID-19.
Labels often stress timing: many antivirals for flu or shingles work best when started soon after symptoms begin. They also list kidney dosing for some, interactions (especially for HIV, hepatitis C and COVID-19 medicines), and specific warnings, such as hepatitis B flaring if certain medicines are stopped. Antibiotics do not work against viruses, and antivirals do not work against bacteria.
Some antivirals keep a long-term virus under control rather than removing it from the body, as with HIV and herpes.
Where you may see it
- 'Indications' sections of flu, herpes, HIV and hepatitis medicine labels
- Pharmacy leaflets ('start within 48 hours of symptoms' where stated)
- Infectious disease clinic letters
📄 How it looks on a report
Initiate treatment as soon as possible after the onset of signs or symptoms.
🙅 What it does not mean
- An antiviral is not an antibiotic.
- One antiviral does not work against every virus.
- It does not always remove the virus from the body; some keep it under control.
🗒️ Questions to ask your doctor
💊 Medicines whose labels mention “Antiviral”
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
- Oseltamivir
An influenza neuraminidase inhibitor, a type of antiviral medicine used against the flu
- Rosuvastatin
a cholesterol-lowering medicine of the statin type (an HMG CoA reductase inhibitor)
- Valacyclovir
an antiviral medicine. The label describes it as a deoxynucleoside analogue DNA polymerase inhibitor, and it is the hydrochloride salt of the L-valyl ester of acyclovir.
🔗 Read more from trusted sources
- “Antiviral” on MedlinePlus ↗
US National Library of Medicine
- NCI Dictionary definition ↗
US National Cancer Institute: “antiviral”
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