What are antivirals?

Antivirals are medications that help your body fight off certain viruses that can cause disease. Antiviral drugs are also preventive. They can protect you from getting viral infections or spreading a virus to others.

What are viruses?

Viruses are tiny (microscopic) infectious agents that grow and multiply only inside living cells of an organism. Viruses have receptors that allow them to attach to healthy (host) cells in your body. Once a virus attaches to and enters a host cell, it can replicate (make copies of itself). The host cell dies, and the virus infects other healthy cells.

Sometimes, viruses remain in a host cell without replicating or damaging it. The virus is still there (which means you could be contagious), but you don’t have symptoms. This latent, or inactive, virus can become active at any time and cause symptoms or be passed on to others. The way viruses spread depends on the type of virus.

Viruses can spread through: modes of viral spread (differs by type of virus):

  • Contaminated bodily products like blood, urine, feces (poop), vomit, ejaculate (semen) and saliva.
  • Bug bites (transfer of a virus from a bug’s saliva into a person’s blood).
  • Skin-on-skin contact, including sex.

How do antiviral medications work?

Antiviral medicines work differently depending on the drug and virus type. Antivirals can:

  • Block receptors so viruses can’t bind to and enter healthy cells.
  • Boost the immune system, helping it fight off a viral infection.
  • Lower the viral load (amount of active virus) in the body.

What do antivirals treat?

Most viruses clear up without antiviral medications. Healthcare providers prescribe antivirals to treat chronic or life-threatening viral infections, including:

Can antivirals cure viral infections?

Antiviral drugs can ease symptoms and shorten how long you are sick with viral infections like the flu and Ebola. They can rid your body of these viruses.

Viral infections like HIV, hepatitis and herpes are chronic. Antivirals can’t get rid of the virus, which stays in your body. However, antiviral medicines can make the virus latent (inactive) so that you have few, if any, symptoms. Symptoms that develop while you take antivirals may be less severe or go away faster.

Can antivirals prevent the spread of viral infections?

Yes, antiviral drugs can keep you from getting certain viral infections after a suspected or known exposure. For instance, taking specific antivirals:

  • During pregnancy lowers the risk of a mother passing HIV to her newborn (babies also receive antiviral medicine after delivery).
  • Daily lowers the risk of giving herpes or HIV to others or getting HIV from an infected partner.
  • Within 72 hours of a potential HIV exposure can lower the chances of getting infected.
  • Within 48 hours of exposure to the flu virus may keep you from getting sick.

How do you take antiviral medications?

Most antivirals are oral drugs that you swallow. But you may also receive antiviral medications as:

· Eyedrops.

· Inhaled powder.

· Injection (shot) into a muscle.

· IV into a vein.

· Topical (skin) ointments or creams.

How long do you need to take antiviral drugs?

Treatment length varies depending on the antiviral drug and viral infection. You may need one dose of an IV drug or a week of oral medicine.

People who have chronic ailments like HIV may take daily antivirals for life. This drug regimen keeps the virus from becoming active. It can prevent the virus from infecting others.

What’s the difference between antibiotics and antivirals?

Antibiotics help the immune system fight off bacterial infections. Bacteria typically reproduce outside of cells, making it easier for medicines to target them. An antibiotic can usually treat many different types of bacterial infections. But the drugs do not affect viruses.

Each antiviral only works against a specific virus. Because viruses inside cells are harder to target, antiviral drugs are more challenging to develop. There are more viruses than antiviral drugs to treat them.

What are the potential side effects of antivirals?

Side effects from antivirals vary depending on the drug type and strength (dosage). You may experience:

What is antiviral resistance?

Skipping doses or starting and stopping an antiviral medicine can allow a virus to change/adapt so that the antiviral is no longer effective. This is antiviral resistance. People who take antivirals for extended periods are more prone to antiviral resistance.

Who shouldn’t take antiviral medications?

Antivirals are relatively safe medicines. Children as young as two weeks, as well as pregnant and breastfeeding individuals, can take certain antiviral medications. Guidelines for who shouldn’t take antivirals vary depending on the drug. Your healthcare provider can determine whether an antiviral medicine is safe for you.

A note from Cleveland Clinic

Antiviral medications can treat certain viruses, putting an end to symptoms. For people with chronic viral infections, antiviral drugs can stop the virus from multiplying and causing problems. The medicine also lowers your chances of giving the virus to others. Your healthcare provider may prescribe an antiviral as a preventive measure if you have a known viral exposure. Taking antiviral medicines for a long time, or failing to take them as prescribed, can lead to antiviral resistance.

Last reviewed by a Cleveland Clinic medical professional on 05/11/2021.

References

  • Britannica. Antiviral Drug. (https://www.britannica.com/science/antiviral-drug) Accessed 5/12/2021.
  • Centers for Disease Control and Prevention. HIV Treatment. (https://www.cdc.gov/hiv/basics/livingwithhiv/treatment.html) Accessed 5/12/2021.
  • Centers for Disease Control and Prevention. What You Should Know About Flu Antiviral Drugs. (https://www.cdc.gov/flu/treatment/whatyoushould.htm) Accessed 5/12/2021.
  • Merck Manual (Consumer Version). Antiviral Drugs. (https://www.merckmanuals.com/home/SearchResults?query=antiviral) Accessed 5/12/2021.
  • Merck Manual (Consumer Version). Overview of Viral Infections. (https://www.merckmanuals.com/home/infections/overview-of-viral-infections/overview-of-viral-infections) Accessed 5/12/2021.
  • National Institutes of Health. Antiviral Drugs That Are Approved or Under Evaluation for the Treatment of COVID-19. (https://www.covid19treatmentguidelines.nih.gov/antiviral-therapy/) Accessed 5/12/2021
  • Razonable RR. Antiviral drugs for viruses other than human immunodeficiency virus. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3184032/) Mayo Clin Proc. 2011;86(10):1009-26. Accessed 5/12/2021.
  • U.S. Food and Drug Administration. Influenza (Flu) Antiviral Drugs and Related Information. (https://www.fda.gov/drugs/information-drug-class/influenza-flu-antiviral-drugs-and-related-information) Accessed 5/12/2021.

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