Top of the page
Common Brand Name(s): Zovirax
This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.
This medication is used in certain people to treat outbreaks of herpes simplex infection of the skin (such as on the genitals), mucous membrane areas (such as the mouth, nose), or brain. It is also used in certain people to treat shingles infection. The viruses that cause these infections live in the body quietly until an outbreak occurs. Acyclovir does not cure these infections, but can speed healing of the sores, decrease pain/itching/formation of new sores, and lower the risk of other problems from the virus (such as infection spreading to other parts of the body/organs, pain even after the sores heal).
This medication is given by slow injection into a vein as directed by your doctor. It is usually given every 8 hours. It should be injected slowly over 1 hour. Do not inject rapidly. Start this medication as soon as signs or symptoms of a herpes infection occur. Dosage is based on your medical condition, weight, and response to treatment.
If you are giving this medication to yourself at home, learn all preparation and usage instruction from your health care professional. Before using, check this product visually for particles or discoloration. If either is present, do not use the liquid. Learn how to store and discard medical supplies safely.
This medication works best when the amount of medicine in your body is kept at a constant level. Use this drug at evenly spaced intervals.
Continue to use this medication until the full prescribed amount is finished, even if symptoms disappear after a few days. Stopping the medication too early may result in a return of the outbreak.
Drink plenty of fluids while receiving this medication unless your doctor directs you otherwise.
Tell your doctor if your condition lasts or gets worse.
Nausea, vomiting, or loss of appetite may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.
Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tell your doctor right away if you have any serious side effects, including:
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Before using acyclovir, tell your doctor or pharmacist if you are allergic to it; or to valacyclovir; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of:
This medication contains sodium. Consult your doctor or pharmacist if you are on a salt-restricted diet or if you have a condition that could be worsened by an increase in salt intake (such as congestive heart failure).
Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).
Do not have certain immunizations/vaccinations (such as vaccines against the varicella virus) without the consent of your doctor.
Older adults may be more sensitive to the side effects of the drug, especially mental/mood changes (such as agitation, confusion).
During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.
This medication passes into breast milk. Consult your doctor before breast-feeding.
Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.
Some products that may interact with this drug include:
Acyclovir is very similar to valacyclovir. Do not use medications containing valacyclovir while using acyclovir.
If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Alberta residents can call PADIS (Poison and Drug Information Service) 24 hours a day at 1-800-332-1414. Canada residents can call a provincial poison control center. Symptoms of overdose may include: change in the amount of urine, seizures, extreme tiredness, loss of consciousness, agitation.
To reduce the risk of spreading genital herpes to others, stop all sexual activity during an outbreak until it is completely healed. At all other times, use effective barrier protections (such as latex or polyurethane condoms, dental dams) during all sexual activity. Consult your doctor or pharmacist for more details.
Lab and/or medical tests (such as kidney function) should be done while you are using this medication. Keep all medical and lab appointments. Consult your doctor for more details.
It is important to get each dose of this medication as scheduled. If you miss a dose, ask your doctor or pharmacist right away for a new dosing schedule. Do not double the dose to catch up.
If you have questions about missing a dose or you don't have more medication, contact your healthcare provider or pharmacist.
Consult the product instructions and your pharmacist for storage details. Keep all medications away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
Information last revised December 2022.
Copyright(c) 2023 First Databank, Inc.
Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.