Antiviral medications for chicken pox
Examples
Generic Name Brand Name acyclovir Zovirax famciclovir Famvir valacyclovir hydrochloride Valtrex Antiviral medications can be taken by mouth (orally) or given by injection into a vein (intravenous, or IV). Acyclovir is the antiviral medication used most often to treat chicken pox (varicella). However, other antivirals may be used.
Antiviral eye ointments are also available. They can be used on your eyes to treat chicken pox blisters.
How It Works
Antiviral medications stop the growth of the chicken pox (varicella-zoster) virus.
Why It Is Used
Antiviral medications may be given to people who have been in contact with someone who has chicken pox. Antiviral medications are generally given to people who are more likely to become seriously ill or develop complications from chicken pox. These medications need to be started within 24 hours of the first signs of chicken pox rash.
Oral antivirals may safely be given to people who:
- Have long-term illnesses, such as skin or lung diseases.
- Are receiving short-term corticosteroid medication, such as people being treated for asthma.
- Are receiving long-term treatment with certain medications containing salicylates, such as people with arthritis.
Intravenous antivirals are usually recommended for:
- People with impaired immune systems.
- Pregnant women with serious complications of chicken pox.
- Babies born early or babies who have a low birth weight and whose mother had chicken pox.
Antiviral eye ointment is recommended for people who have chicken pox blisters in their eyes.
These medications are usually NOT recommended for:
- Healthy people as a way to prevent them from having chicken pox if they have been exposed to the illness.
- Pregnant women unless they have complications of chicken pox.
Parents of an otherwise healthy child may want their child to have an antiviral medication to shorten the time the child is ill or reduce the severity of symptoms. However, parents may choose not to give antiviral medications to their otherwise healthy child because his or her symptoms are not severe or the illness is not causing problems for the family.
Antiviral medications may work best to protect family members of a person with chicken pox from getting chicken pox.
- Often the first person in a family to get chicken pox is not able to get an antiviral medication soon enough (within 24 hours of the first sign of rash).
- Other family members have time to look for the first signs of chicken pox and watch for the chicken pox rash. At the first sign of rash, they can take an antiviral medication. Other family members are also more likely to have severe symptoms because they have been in close contact with someone who has chicken pox and have been exposed to higher concentrations of the virus.
How Well It Works
Antiviral medications may shorten the length of illness from chicken pox, cause fewer blisters to form, and help blisters heal faster.
Antiviral medications may reduce by 20% the number of days a person is sick with chicken pox (for example, from 5 days to 4) and the number of chicken pox spots (for example, from 200 spots to 160).
It is not known whether antiviral medications reduce the chance of developing complications of chicken pox. Antiviral medications may reduce the complications of chicken pox, such as varicella pneumonia, in people with impaired immune systems.
Side Effects
Antiviral medications have few side effects. They include:
- Headache or feelings of general illness (malaise).
- Nausea and vomiting.
- Diarrhea or constipation. This is rare.
- Kidney problems in people who receive large doses of acyclovir by rapid injection into a vein. This is rare.
The effect of antiviral medications on pregnant women and their fetuses is not known.
The effect of antiviral medications on immunity to chicken pox is not known.
See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)
What To Think About
Consider the following when deciding whether to treat a family member with antiviral medications:
- Antiviral medications are expensive. But the cost of medication is usually covered under provincial health plans or private health insurance.
- Treatment with antiviral medications may reduce the length of time you can pass the chicken pox virus to other people.
- It is not clear whether antiviral medications reduce lost time from work, school, or day care.
Acyclovir (Zovirax) is the most prescribed antiviral medication. It has fewer side effects than the other antiviral medications. However, it does not reduce itching, nor does it stop the spread of the chicken pox virus from one person to another.
People who take acyclovir need to drink extra liquids to prevent kidney problems. People who have kidney problems need to take a lower dose of acyclovir.
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| Author: | Douglas Dana Amy Fackler, MA Debby Golonka, MPH | Last Updated: August 25, 2006 |
| Medical Review: | Adam Husney, MD - Family Medicine Michael J. Sexton, MD - Pediatrics Thomas Emmett Francoeur, MDCM, CSPQ, FRCPC - Pediatrics | |
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| Topic Contents | |
| Examples | |
| How It Works | |
| Why It Is Used | |
| How Well It Works | |
| Side Effects | |
| What To Think About | |