What Is Valtrex (Valacyclovir)?
Valacyclovir is an antiviral agent used to treat the herpes virus, including chickenpox, cold sores, shingles, and genital herpes in children and adults. Though valacyclovir will not cure the virus, it is helpful in inhibiting the spread and lessening the symptoms of a herpes outbreak.
Valacyclovir may be used in children 12 and up to treat cold sores. It may be used in children 2 and over to treat the symptoms of chickenpox.
In addition to treating herpes, valacyclovir may also be prescribed “off-label” to treat other illnesses.
Important Facts about Valtrex (Valacyclovir)
Prior to taking valacyclovir, discuss any medications you are taking with your doctor. This medication may cause kidney damage. Some medications — particularly medications that can harm the kidneys —may interact negatively with valacyclovir and increase the chance of kidney damage.
If you have a compromised immune system, kidney disease, HIV or AIDS or if you have undergone dialysis or a kidney or bone marrow transplant, speak to your physician about the risks/benefits of using this drug.
Use of Valtrex (Valacyclovir)
Use valacyclovir as soon as you experience symptoms of the herpes virus. Symptoms of herpes include: skin tingling, itching, burning, blistering, or sores. Waiting a day or two may lesson this medication’s effectiveness in slowing the progress of the herpes virus.
Take this medication only as prescribed. Do not alter your dosage without first speaking to your physician.
If taking the liquid solution of valacyclovir, shake it thoroughly to ensure that it is properly mixed, then measure out your dose using a medicine cup or marked spoon available from your pharmacist. Do not use a table spoon, as the holding capacity of regular spoons varies and may not be accurate to your dosing instructions.
Store valacyclovir tablets away from moisture or extreme heat, at room temperature.
Store liquid suspension valacyclovir in a refrigerator set below freezing. Throw out any unused valacyclovir after 28 days.
Take valacyclovir with or without food.
Drink an 8 ounce glass of water when you take this medication, and be sure to hydrate throughout the day to prevent a build-up of valacyclovir in your kidneys, which could lead to kidney damage.
Take this medication for the length of time prescribed by your doctor. Though your symptoms may improve rapidly, the herpes infection can still be active for several days after starting valacyclovir.
Valacyclovir will not prevent the spread of herpes. It is possible to transmit herpes even when you are asymptomatic, and taking this medication will not prevent contagion. Refrain from sexual intercourse and activity, or use a latex condom to help prevent the spread of genital herpes when infected. Wash your hands thoroughly after contact with herpes lesions, and avoid touching your eyes or others to lessen the chance of transmitting the virus to other persons or parts of your body.
Pregnant mothers should take extra precautions to prevent a herpes outbreak from spreading near their date of expectancy. The herpes virus may be spread to an infant during delivery and can cause serious health complications.
Children should only take valacyclovir when prescribed by their physician.
Discontinue use of valacyclovir if you experience any of the following: a skin rash (aside from one caused by the virus), vomiting, weakness, unusual bruising, bleeding, yellowing of the skin or eyes, blood in a loose stool, fever, or difficulty with or lessening of urination. These symptoms may indicate damage to your red blood cells, so speak with your doctor immediately if you have any of these conditions.
Important Considerations when Taking Valtrex (Valacyclovir)
If you have HIV/AIDS or any condition that compromises your immune system, speak to your doctor before taking this medication. If you have had a bone marrow or kidney transplant, suffer from kidney disease, or are currently undergoing kidney dialysis, your doctor may need to adjust the dosage of valacyclovir or perform certain laboratory tests to ensure the medication is safe for you to take.
Elderly patients may experience harmful side effects while taking this medication and should consult their physician as to the risks/benefits of Valtrex treatment.
Do not take Valtrex if you have ever experienced an allergic reaction to Zovorax (acyclovir) or valacyclovir.
This medication should not be used by mothers who are nursing infants, as it can be passed through the breast milk and may cause harm to your child. Speak with your physician if you are breast feeding.
Valacyclovir is rated as a category “B” drug by the Food and Drug Administration (FDA) and is considered most likely safe to use during pregnancy. Since herpes may be transmitted to your child during childbirth and can cause serious health consequences for your newborn, reducing the risk of a herpes outbreak is of the utmost importance for expectant mothers in the last trimester of pregnancy.
Valtrex (Valacyclovir) and Drug Interactions
Valacyclovir may cause damage to your kidneys. Certain drugs may interact with valacyclovir and increase the chance of kidney harm. These include:
- other antiviral agents, including: adefovir (Hepsera), cidofovir (Vistide), or foscarnet (Foscavir)
- organ transplant rejection medications, including: sirolimus (Rapamune) or tacrolimus (Prograf)
- pain medications and medication used to alleviate arthritis symptoms, including: aspirin (Anacin, Excedrin), acetaminophen (Tylenol), diclofenac (Voltaren), etodolac (Lodine), ibuprofen (Advil, Motrin), indomethacin
- methotrexate (Rheumatrex, Trexal)
- IV antibiotics, including: amphotericin B (Fungizone, AmBisome, Amphotec, Abelcet), amikacin (Amikin), bacitracin (Baci-IM), capreomycin (Capastat), gentamicin (Garamycin), kanamycin (Kantrex), streptomycin, or vancomycin (Vancocin, Vancoled)
- medicine used to treat certain forms of cancer, including: aldesleukin (Proleukin), carmustine (BiCNU, Gliadel), cisplatin (Platinol), ifosfamide (Ifex), oxaliplatin (Eloxatin), plicamycin (Mithracin), streptozocin (Zanosar), or tretinoin (Vesanoid)
- ulcerative colitis medications, including: mesalamine (Pentasa) or sulfasalazine (Azulfidine)
- lithium (Eskalith, Lithobid)
This is not a complete list of medications that can interact with valacyclovir. Speak with your doctor about any prescription or over-the-counter medications and/or vitamins, minerals, herbs, or supplements you are taking prior to, or while, using this medication.
Possible Side Effects of Valtrex (Valacyclovir)
Call 9-1-1, or seek emergency assistance if you experience symptoms of an allergic reaction to valacyclovir. These symptoms may include: facial swelling, swelling of the mouth, tongue, or throat, hives, extreme itching, or problems breathing.
Stop taking this medication, and call your physician immediately if you experience: muscle weakness, unusual bruising, loose, bloody stools, fever, fainting, yellowing of the skin or eyes or extreme paleness, spotting of the skin that is not associated with the herpes or chickenpox virus, or vomiting. These may be signs of red blood cell damage –a potential side effect of this medication.
Contact your doctor immediately if you experience:
- Blurry vision or problems with speaking
- Convulsions or seizures
- Increased thirst, change in appetite, nausea, or vomiting
- Unusual moodiness or irritability
- Drowsiness, or trouble concentrating
- Aggression, hallucinations, extreme agitation
- Unusual weight gain or swelling
- Lower back pain
- Difficulty with movement
Notify your doctor if you have symptoms of minor side effects, including: a stuffy nose, throat pain, stomach pain, nausea, cramping, menstrual pain, joint pain, a slight skin rash, depression, dizziness, headaches, or a feeling of tiredness or general malaise.
Speak to your doctor about any other side-effects you may experience while taking valacyclovir, and report them to the FDA by calling 1-800-FDA-1088.
Valtrex (Valacyclovir) Overdose
If you think you may have accidentally taken too much valacyclovir, or if you experience a reduction or complete cessation of urination, seek emergency medical assistance.
If you miss a dose of valacyclovir, take the medication as soon as you can. If it is close your next scheduled dose, wait until it is time for your next dose to take the medication. Do not double up on valacyclovir to compensate for a missed dose.