Valacyclovir tablets are a prescription antiviral medicine. Valacyclovir tablets lower the ability of herpes viruses to multiply in your body.
- to treat cold sores (also called fever blisters or herpes labialis)
- to treat shingles (also called herpes zoster)
- to treat or control genital herpes outbreaks in adults with normal immune systems
- to control genital herpes outbreaks in adults infected with the human immunodeficiency virus (HIV) with CD4 + cell count greater than 100 cells/mm3
- with safer sex practices to lower the chances of spreading genital herpes to uninfected partners. Even with safer sex practices, it is still possible to spread genital herpes. Valacyclovir tablets used daily with the following safer sex practices can lower the chances of passing genital herpes to your partner.
- Do not have sexual contact with your partner when you have any symptom or outbreak of genital herpes.
- Use a condom made of latex or polyurethane whenever you have sexual contact.
- to treat cold sores (for children ≥ 12 years of age)
- to treat chickenpox (for children 2 to < 18 years of age)
Valacyclovir tablets do not cure herpes infections (cold sores, chickenpox, shingles, or genital herpes). The efficacy of valacyclovir tablets has not been studied in children who have not reached puberty.
Do not take valacyclovir tablets if you are allergic to any of its ingredients or to acyclovir. The active ingredient is valacyclovir.
Before taking valacyclovir tablets, tell your healthcare provider: About all your medical conditions, including:
- if you have had a bone marrow transplant or kidney transplant, or if you have advanced HIV disease or “AIDS”. Patients with these conditions may have a higher chance for getting a blood disorder called thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS). TTP/HUS can result in death.
- if you have kidney problems. Patients with kidney problems may have a higher chance of side effects or more kidney problems with valacyclovir tablets. Your healthcare provider may give you a lower dose of valacyclovir tablets.
- if you are 65 years of age or older. Elderly patients have a higher chance of certain side effects. Also, elderly patients are more likely to have kidney problems. Your healthcare provider may give you a lower dose of valacyclovir tablets.
- if you are pregnant or planning to become pregnant. Talk with your healthcare provider about the risks and benefits of taking prescription drugs (including valacyclovir tablets) during pregnancy.
- if you are breast-feeding. Valacyclovir tablets may pass into your milk and it may harm your baby. Talk with your healthcare provider about the best way to feed your baby if you are taking valacyclovir tablets.
- about all the medicines you take, including prescription and non-prescription medicines, vitamins and herbal supplements. Valacyclovir tablets may affect other medicines, and other medicines may affect valacyclovir tablets. It is a good idea to keep a complete list of all the medicines you take. Show this list to your healthcare provider and pharmacist any time you get a new medicine.
Certain people should not take valacyclovir and others should use decreased doses of valacyclovir. Below are some important examples.
Sensitivity or Allergies: Patients with sensitivity or an allergy to any of the following medications should not use Valacyclovir: Acyclovir, Famciclovir, ganciclovir, penciclovir, valacyclovir, or valganciclovir.
Kidney Issues: Dose adjustments should be made for those with kidney impairment or issues. Decreased doses are needed as kidney impairment slows the clearing from the body of valacyclovir. The degree of impairment determines the decrease in the dosage. The PDR states, “Acute renal failure and CNS (Nervous System) toxicity have been reported in patients with underlying renal (Kidney) dysfunction who have received inappropriately high doses of valacyclovir for their level of renal (Kidney) function. Patients receiving potentially nephrotoxic (Toxic to the Kidney) drugs together with valacyclovir may have an increased risk of renal dysfunction (impairment).”
The Elderly: The elderly are more likely to have impaired kidneys so they might not clear valacyclovir from their system as efficiently as they should. This can lead to inappropriately high levels of valacyclovir, which means the elderly may need lower doses of valacyclovir. The elderly are also more likely to experience neurological side effects, including: agitation, hallucinations, confusion, delirium, and other abnormalities of brain function termed encephalopathy.
Dehydration: When patients are dehydrated acyclovir can reform as a solid in the kidney leading to kidney damage. Patients should all remain well hydrated when taking valacyclovir.
Pregnancy: While a registry that collected data on the 756 pregnancies of women exposed to acyclovir in the first trimester showed no greater occurrence of birth defects than occurs in the general population, the study size was too small to guarantee safety during pregnancy.
You should not take Valacyclovir if you are pregnant or trying to become pregnant unless recommended by your obstetrician/gynecologist or other healthcare provider.
Breastfeeding: The PDR states, “According to the manufacturer, valacyclovir should be administered to a nursing mother with caution and only when indicated. Although the American Academy of Pediatrics (AAP) has not specifically evaluated valacyclovir, systemic maternal acyclovir is considered to be usually compatible with breastfeeding…Consider the benefits of breastfeeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition.”
See here for other special groups, warnings, and precautions
Withholding or providing inaccurate information about your health and medical history in order to obtain treatment may result in harm, including, in some cases, death.
Tell your healthcare provider about your medical history before taking valacyclovir. This means letting them know about all of the medications and supplements you are taking, as well as any information about other health conditions you may have. It may also be helpful for your healthcare provider to understand whether you are taking valacyclovir for cold sores or for genital herpes and the number of outbreaks you typically experience per year, if you have this information.
- Take valacyclovir tablets exactly as prescribed by your healthcare provider. Your dose of valacyclovir tablets and length of treatment will depend on the type of herpes infection that you have and any other medical problems that you have.
- Do not stop valacyclovir tablets or change your treatment without talking to your healthcare provider.
- Valacyclovir tablets can be taken with or without food.If you are taking valacyclovir tablets to treat cold sores, chickenpox, shingles or genital herpes, you should start treatment as soon as possible after your symptoms start. Valacyclovir tablets may not help you if you start treatment too late.
- If you miss a dose of valacyclovir tablets, take it as soon as you remember and then take your next dose at its regular time. However, if it is almost time for your next dose, do not take the missed dose. Wait and take the next dose at the regular time.
- Do not take more than the prescribed number of valacyclovir tablets each day. Call your healthcare provider right away if you take too much valacyclovir tablets.
What follows is a summary and does not include every side effect possible. Please, read the package insert for a comprehensive list of side effects.
Very common side effects (may affect more than 1 in 10 people): headache. The most common side effect seen in children < 18 years of age was headache.
Common side effects (may affect up to 1 in 10 people) include feeling sick, dizziness, vomiting, diarrhea, skin reaction after exposure to sunlight (photosensitivity), rash, itching (pruritus). Side effects in HIV-infected adults include headache, tiredness and rash. These side effects usually are mild and do not cause patients to stop taking valacyclovir tablets.
Uncommon side effects (may affect up to 1 in 100 people) include feeling confused, seeing or hearing things that aren’t there (hallucinations), feeling very drowsy, tremors, feeling agitated. These nervous system side effects usually occur in people with kidney problems, the elderly or in organ transplant patients taking high doses of 8 grams or more of valacyclovir a day. They usually get better when valacyclovir is stopped or the dose reduced.
Other less common side effects in adults include painful periods in women, joint pain, depression, low blood cell counts and changes in tests that measure how well the liver and kidneys work.
Other uncommon side effects: shortness of breath (dyspnea), stomach discomfort, rash, sometimes itchy, hive-like rash (urticaria), low back pain (kidney pain), blood in the urine (hematuria)
Uncommon side effects that may show up in blood tests: reduction in the number of blood platelets, which are cells that help blood to clot (thrombocytopenia), reduction in the number of white blood cells (leukopenia), increase in substances produced by the live
Rare side effects (may affect up to 1 in 1,000 people) include unsteadiness when walking and lack of coordination (ataxia), slow, slurred speech (dysarthria), fits (convulsions), altered brain function (encephalopathy), unconsciousness (coma), confused or disturbed thoughts (delirium). Like the nervous system side effects listed above, these side effects also usually occur in people with kidney problems, the elderly or in organ transplant patients taking high doses of 8 grams or more of valacyclovir a day (higher than the maximum doses used for any indication). They usually get better when valacyclovir is stopped or the dose reduced.
Other rare side effects: kidney problems where you pass little or no urine.
Kidney failure and nervous system problems are not common, but can be serious in some patients taking valacyclovir. Kidney problems could potentially be more likely in people with existing kidney issues and/or inadequate hydration who are taking valacyclovir long term. Potential nervous system problems could include shaky movements, confusion, and seizures and coma in more serious cases. Additionally, long term use of valacyclovir could lead to inflammation of the liver in some people, especially those with existing health issues affecting the liver.
Severe allergic reactions are rare in people taking valacyclovir. Anaphylaxis is marked by the rapid development of flushing, itchy skin rash, swelling of the lips, face, neck, and throat—causing difficulty in breathing (angioedema), fall in blood pressure leading to collapse. If any of these occur, get emergency treatment immediately.
Nervous system problems include aggressive behavior, unsteady movement, shaky movements, confusion, speech problems, hallucinations (seeing or hearing things that are really not there), seizures and coma.
Kidney failure and nervous system problems have happened in patients who already have kidney disease and in elderly patients whose kidneys do not work well due to age. Always tell your healthcare provider if you have kidney problems before taking valacyclovir tablets.
Call your doctor right away if you get a nervous system problem while you are taking valacyclovir tablets.
Talk to your healthcare provider if you develop any side effects that concern you. These are not all the side effects of valacyclovir tablets. For more information ask your healthcare provider or pharmacist.
Keep valacyclovir tablets and all medicines out of the reach of children. General information about valacyclovir tablets Medicines are sometimes prescribed for conditions that are not mentioned in patient information leaflets. Do not use valacyclovir tablets for a condition for which it was not prescribed. Do not give valacyclovir tablets to other people, even if they have the same symptoms you have. It may harm them.
If you are experiencing a medical emergency, call 911 or seek immediate medical attention.
You are encouraged to report negative side effects of prescription products to the FDA. Visit www.fda.gov/medwatch or call 1-800-FDA-1088.
Please see the full Prescribing Information for complete safety information.
There are no clinically significant drug-drug interactions with valacyclovir listed on the drug label. That being said, you should always let your healthcare provider know about all the medications you are taking to determine whether there is a potential for interactions.
Alcohol does not seem to affect the way that valacyclovir works, and there are no alcohol warnings specifically listed on valacyclovir’s drug label. However, excessive alcohol consumption is not recommended as it can impair the immune system.
