acyclovir
Acyclovir is an antiviral oral medication used to treat infections caused by the herpes virus, including shingles, chickenpox, and genital herpes. It comes as a tablet, capsule, and liquid suspension. Depending on your condition, you might need to take it by mouth 2 to 5 times a day. Acyclovir works best when you start it as soon as symptoms begin. Common side effects include nausea, vomiting, and diarrhea.
What is Acyclovir?
What is Acyclovir used for?
- Genital herpes in adults
- Shingles in adults
- Chickenpox in people 2 years and older
How Acyclovir works
Acyclovir is an antiviral medication, specifically a herpes virus nucleoside analogue. It works by blocking the herpes virus from making new DNA, which stops the virus from multiplying in your body.
Drug facts
More on Acyclovir essentials
Side effects of Acyclovir
The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.
Common Side Effects
Genital herpes:
- Nausea/vomiting (3-5%)
- Diarrhea (2%)
Shingles
- Feeling unwell (12%)
Chickenpox
- Diarrhea (3%)
Less Common Side Effects
- Headache
- Pain
- Sleepiness
- Dizziness
- Muscle pain
- Hives
- Vision problems
The following Acyclovir side effects have also been reported
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
More common
Mild pain, burning, or stinging
Less common
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Get your GoodRx coupon
Pros and cons of Acyclovir
Pros
- Available in tablet, capsule, and liquid forms
- Safe for children 2 years and older
- Can shorten how long outbreaks last
- Not many interactions with other medications
Cons
- Must be taken multiple times per day
- Can cause unpleasant stomach side effects, like nausea and diarrhea
- Not available over the counter
- Doesn't cure herpes infection
Pharmacist tips for Acyclovir
- Acyclovir works best when you start it as soon as you notice signs of an outbreak or infection. For shingles, take acyclovir within 72 hours of the rash appearing, and for chickenpox, within 24 hours of the rash appearing.
- Acyclovir needs to be taken several times a day, which can be hard to keep up with. Using a phone alarm or a pill box can help you remember every dose.
- Finish your full treatment course of acyclovir, even if you feel better. Don’t stop unless your prescriber tells you to.
- If you're taking acyclovir liquid suspension, shake the bottle well before each dose and only use the measuring device provided by your pharmacist.
- Drink plenty of water while taking acyclovir. Staying hydrated helps lower the risk of kidney damage.
- Acyclovir won't cure genital herpes, but it helps shorten outbreaks and speeds healing. Avoid sexual contact during outbreaks and practice safe sex, such as using condoms.
Common questions about Acyclovir
How long it takes for acyclovir to work depends on the type of infection you have, how severe it is, and how quickly you start treatment. Most of the time, you’ll need to take acyclovir for 5 to 10 days, even if your symptoms start to get better before then. Always finish the full course as prescribed, because stopping too early can make your infection worse.
No, acyclovir isn't an antibiotic. It's an antiviral, and only works against the herpes virus. If you have a bacterial infection, you'll need a different medication to treat it.
No, acyclovir doesn’t usually cause yeast infections. If you notice symptoms of a yeast infection while taking this medication, let your prescriber know to make sure nothing else is causing it.
It isn’t known for sure if acyclovir is safe to take during pregnancy because there haven’t been enough well-designed studies in people. But one study looked at over 1,500 babies exposed to acyclovir in the first trimester and found no higher risk of birth defects compared to the rest of the population. If you’re pregnant or planning to get pregnant, talk with your prescriber about the risks and benefits of taking this medication.
No, acyclovir isn't over the counter. It requires a prescription from a healthcare professional.
Yes, acyclovir can commonly cause diarrhea. If your diarrhea doesn’t go away or becomes severe, let your care team know.
Acyclovir can stay in your system for 10 to 17 hours after your last dose. This is based on its half-life, which measures how long it takes for half of the medication to leave your body. If you have kidney problems, acyclovir can stay in the body longer, so your prescriber might need to adjust your dose.
Acyclovir doesn't commonly cause tiredness. If you feel very tired or weak while taking this medication, let your prescriber know to make sure it isn’t from another cause.
How to save using GoodRx
Risks and warnings for Acyclovir
Acyclovir can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Kidney problems
- Risk factors: Older adults | Low fluids in the body | Taking other medications that harm the kidneys
Acyclovir can sometimes cause serious kidney problems, especially in older adults. Your risk is higher if you get dehydrated or take other medications that can harm the kidneys, like ibuprofen or naproxen. Be sure to drink plenty of fluids while taking acyclovir, and talk to your prescriber before using any other medication, even over-the-counter pain or cold products. Your prescriber might also order lab tests to check your kidney health.
Blood clotting problems
- Risk factors: Medical conditions that weaken your immune system
It's rare, but some people have had serious blood clotting problems while taking acyclovir. This has mostly been seen in people with a weakened immune system. Your prescriber might order labs to check your blood work while you're taking this medication. Call your prescriber right away if you notice fever, unusual bleeding or bruising, confusion, extreme tiredness, or headaches.
Acyclovir dosage
Tablet| Dosage | Quantity | Price as low as | Price per unit |
|---|---|---|---|
| 400mg | 30 tablets | $12.31 | $0.41 |
| 800mg | 30 tablets | $14.57 | $0.49 |
Typical dosage for Acyclovir
Acyclovir is available as a capsule, tablet, and liquid suspension. Your dose will depend on the reason you're taking the medication. In general:
- Shingles: The typical dose is 800 mg by mouth every 4 hours (5 times a day) for 7 to 10 days.
- Genital herpes:
- Treatment for initial infection: The typical dose is 200 mg by mouth every 4 hours (5 times a day) for 10 days.
- Daily treatment to prevent infections: The typical dose is 400 mg by mouth twice a day for up to a year.
- As-needed treatment: The typical dose is 200 mg by mouth every 4 hours (5 times a day) for 10 days.
- Chickenpox:
- Adults and children over 40 kg: The typical dose is 800 mg by mouth 4 times a day for 5 days.
- Children (2 years and older under 40 kg): The typical dose is 20 mg/kg of body weight by mouth 4 times a day for 5 days.
Your dose might differ if you have kidney problems.
Interactions between Acyclovir and other drugs
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
How much does Acyclovir cost?
Acyclovir contraindications
Contraindications are specific health conditions or situations in which a person should not take a medication due to safety concerns. If you have any of the following conditions or if any of the following apply to you, let your healthcare provider know because Acyclovir will not be safe for you to take.
- Allergy to acyclovir or valacyclovir
What are alternatives to Acyclovir?
News about Acyclovir
Acyclovir images
