What Is Acyclovir (Zovirax)?
The Food and Drug Administration (FDA) approved acyclovir to treat viral infections from the varicella virus that causes chicken pox and shingles, as well as infections from the virus that causes genital herpes.
Sometimes doctors prescribe acyclovir to treat herpes infections in people with HIV.
The drug works by preventing viruses from dividing and multiplying. The FDA approved acyclovir in the 1980s.
Acyclovir is available as a generic, made by several companies, or under the brand name Zovirax, made by GlaxoSmithKline and available in tablet, capsule, and liquid form.
Acyclovir is one of the oldest drugs used to treat herpes simplex viruses and remains the first line of treatment for these infections.
However, research shows that acyclovir is not as effective as it used to be.
A 2013 study, published in the journal Current Opinion in Infectious Diseases, found that acyclovir-resistant herpes strains could develop over time.
Resistance happens in people with a healthy immune system as well as in those with a weakened immune system.
Acyclovir Warnings
It's important to know that acyclovir does not cure viral infections. However, it can make infections shorter and less serious for some people.If you're taking acyclovir for genital herpes, it can reduce the severity or prevent recurrences of a herpes outbreak.
If you're taking acyclovir to treat chicken pox or shingles, the drug can reduce the severity of your infection.
It's important to know that treatment with acyclovir works best when you start taking it as soon as possible after a rash appears.
This means within three days of a shingles rash and within 24 hours of a chicken pox rash.
It's usually not necessary to treat young, healthy children with chicken pox, but older children or adults who get chicken pox may need treatment.
Drink plenty of fluids when taking this medication. Children younger than 2 should not take acyclovir.
Use acyclovir with caution if you have kidney disease or any condition that weakness your immune system. If you have these conditions, you could be at risk for serious reactions to acyclovir.
Ask your doctor for advice on practicing safe sex if you have a genital herpes infection. Genital herpes spreads through sexual activity, and taking acyclovir alone may not be enough to prevent it.
Acyclovir and Pregnancy
If you're a woman, let your doctor know if you are or may be pregnant or if you're breastfeeding.Researchers have not studied acyclovir use by pregnant women, so there's not enough evidence to say that it is safe to take during pregnancy.
Acyclovir also may pass into breast milk.
Acyclovir Side Effects
Shingles requires treatment with higher doses of acyclovir, and the most common side effects at higher doses are tiredness and malaise.
Tell your doctor if you have any side effects. Side effects that may be seen in all people using acyclovir include:
- Nausea
- Diarrhea
- Vomiting
- Headache
- Dizziness
- Tiredness
- Muscle or joint aches
- Visual changes
- Fluid retention
- Hair loss
- Confusion
- Changes in behavior
- Severe rash, hives, or a rash that causes blisters and peeling
- Yellowing of skin or eyes
- Unusual bleeding or bruising
- Seizure
- Loss of consciousness
- Swelling of face, lips, or tongue
- Difficulty breathing
- Decreased urine output or blood in the urine
- Extreme sleepiness or confusion
- Hallucinations
- Tingling, numbness, or shakiness
Acyclovir Interactions
It's very important to let your doctor know about all drugs you are taking, including any over-the-counter herbs or supplements.
Drugs that may interact with acyclovir include:
- Several medications used to treat bacterial or fungal infections, including amphotericin B (Fungizone) and several antibiotics such as amikacin (Amikin), gentamicin (Garamycin), kanamycin (Kantrex) and tobramycin (Tobi, Nebcin)
- Over-the-counter pain relievers (Advil, Motrin, Aleve)
- Medications used to treat HIV/AIDS, such as zidovudine (Retrovir, AZT)
Other Acyclovir Interactions
You do not need to change your diet or your activities while on acyclovir.However, drink plenty of fluids when taking this medication.
Acyclovir Dosage
Acyclovir comes in tablets, capsules, and liquid form. You can take it with or without food.
Lower doses may be best for elderly people and for anyone with kidney disease.
Common dosages are:
- For treatment of shingles: 800 milligrams (mg) five times daily for 7 to 10 days
- For genital herpes treatment: 200 mg five times daily for 10 days
- For preventing a recurrence of genital herpes: 400 mg every 12 hours for 12 months
- For treating chicken pox in adults and children who weigh more than 40 pounds: 800 mg four times daily for 5 days
Acyclovir Overdose
An overdose of acyclovir can cause kidney damage.Symptoms of an overdose may include:
- Agitation
- Extreme sleepiness
- Loss of consciousness
- Seizures
- Kidney failure (no urine production)
If you or someone else has any severe symptoms after an overdose, call 9-1-1.
Missed Dose of Acyclovir
You should take acyclovir exactly as directed by your doctor. Also, do not stop taking acyclovir on your own.Skipping doses or stopping too soon may not completely treat your infection, or it could make the infection harder to treat.
If you miss a dose of acyclovir, take the missed dose as soon as you remember.
If it's almost time for your next dose, skip the missed dose.
Do not double your dose to make up for a missed dose.
Acyclovir (Zovirax) Pictures
