Valacyclovir (important antiviral drug information)

2021-06-28 04:24 AM

Valacyclovir will not stop the spread of genital herpes. Herpes infection is contagious and can infect others, even while taking this medicine.

Generic Name: valacyclovir.

Brand: Valtrex.

What is Valacyclovir?

Valacyclovir is an antiviral drug. It slows the growth and spread of the herpes virus. It does not cure herpes, but it can ease the symptoms of the infection.

Valacyclovir is used to treat infections caused by the herpes virus in adults and children. Diseases caused by the herpes virus include genital herpes, cold sores, shingles, and chickenpox.

Valacyclovir is used to treat herpes in children who are at least 12 years old, and to treat chickenpox in children who are at least 2 years old.

Valacyclovir may also be used for other purposes not listed in this medication guide.

Important Information

Before taking valacyclovir, tell your doctor if you have HIV/AIDS, a weakened immune system, kidney disease (or if you are on dialysis), or if you have had a kidney or bone marrow transplant.

Valacyclovir can damage the kidneys, and these effects are increased when it is used with other medicines that can damage the kidneys. Tell your doctor about all the other medicines you are taking. Dose adjustments or special tests may be needed when certain medicines are taken with valacyclovir.

Treatment with valacyclovir should be initiated as soon as possible after the appearance of the first symptoms (eg, itching, burning, blisters).

Herpes virus can be passed from mother to baby during birth. If genital herpes is present, preventing herpes lesions during pregnancy is important so that there are no genital lesions when the baby is born.

Valacyclovir will not stop the spread of genital herpes. Herpes infection is contagious and can infect others, even while taking this medicine.

Stop taking valacyclovir and call your doctor at once if you have any signs of a serious side effect that can damage red blood cells, such as fever, easy bruising or bleeding, spotting redness on the skin (not related to herpes or chickenpox), bloody diarrhea, vomiting, pale or yellow skin, weakness, fainting, or urinating less than usual or not at all.

Do not give valacyclovir to a child unless it has been prescribed by a doctor.

Before taking this medicine

Do not take this medicine if you are allergic to valacyclovir or acyclovir (Zovirax).

If there are certain problems, a dose adjustment or special tests may be needed to take this medicine safely. Before taking valacyclovir, tell your doctor if you have:

HIV/AIDS, or other problems that can weaken the immune system;

Kidney disease (or if you are on dialysis); or

If you have had a kidney or bone marrow transplant.

Valacyclovir is not expected to harm an unborn baby. However, the herpes virus can be passed from mother to baby during birth. If genital herpes is present, preventing herpes lesions during pregnancy is important so that there are no genital lesions when the baby is born. Valacyclovir passes into breast milk and may harm a nursing infant. Do not take this medicine without telling your doctor if you are breastfeeding a baby. Do not give this medicine to a child unless it has been prescribed by a doctor.

Older adults may be more likely to have harmful side effects when taking valacyclovir. Talk to your doctor about specific risks.

How should valacyclovir be taken?

Take valacyclovir exactly as it was prescribed. Do not take the medicine in larger amounts, or for longer than recommended by your doctor. Follow the directions on the medicine label.

Treatment with valacyclovir should be started as soon as possible after the first appearance of symptoms (eg, itching, burning, blisters). This medicine may not be effective if you first start taking it 1 or 2 days after the onset of symptoms.

Take each dose with a full glass of water. Drink lots of water while you are taking valacyclovir to keep your kidneys working properly. Shaking the oral suspension (liquid) is also required just before a dose is measured. To be sure to get the correct dose, measure the liquid with a spoon or cup, not with a regular spoon. If you do not have a dosimeter, ask your pharmacist.

Valacyclovir can be taken with or without food.

Take this medication for the entire length of time prescribed by your doctor. Symptoms may get better before the infection is completely treated. Valacyclovir will not treat viral infections such as cold or other common flu.

Lesions caused by the herpes virus should be kept as clean and dry as possible. Wearing loose clothing can help prevent irritation of the lesions.

Store valacyclovir tablets at room temperature away from moisture and heat. Store the liquid in the refrigerator. Do not freeze. Throw away any unused liquid valacyclovir older than 28 days.

What happens if a dose is missed?

Take that dose as soon as you remember. If it is almost time for the next dose, skip the missed dose and take the medicine at the next regularly scheduled time. Do not take extra medicine to make up for the missed dose.

What happens if you overdose?

Seek emergency medical attention if you think too much of this medicine has been used.

Overdose symptoms may include urinating less than usual or not at all.

What should be avoided?

Valacyclovir will not stop the spread of genital herpes. Herpes infection is contagious and can infect others, even while taking this medicine.

Avoid intercourse or use condoms to prevent spreading the virus to others. Avoid contact of infected areas with other people. Avoid touching the infected area and then touching your eyes. Wash your hands often to avoid spreading the disease to others.

Valacyclovir side effects

Get emergency medical help if you have any of these signs of an allergic reaction to valacyclovir: hives; shortness of breath; swelling of the face, lips, tongue, or throat.

Stop taking valacyclovir and call your doctor at once if you have any of the following signs of a serious side effect that can damage red blood cells:

fever, easy bruising or bleeding;

Red spots on the skin (not related to herpes or chickenpox);

bloody diarrhea, vomiting;

Pale or yellow skin;

Weakness or fainting; or

Urinating less than usual or not at all.

Call your doctor right away if you have any of these other serious side effects:

Pain in the lower back;

Drowsiness, mood swings, thirst, loss of appetite, nausea, and vomiting;

swelling, weight gain, feeling short of breath;

Confusion, agitation, aggression, hallucinations, difficulty concentrating;

Feeling shaky or unsteady;

Problems with speech or vision; or

Seizures (convulsions).

Less serious valacyclovir side effects may include:

Nausea, stomach pain;

headache, dizziness, feeling tired, depression;

Arthritis;

Dysmenorrhea;

mild skin rash; or

Nasal congestion, sore throat.

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effects.

Valacyclovir quantitative information

Usual Adult Dose for Herpes Simplex Blisters:

2 g of valacyclovir orally every 12 hours for a total of 2 doses (4 g).

Treatment should be initiated at early signs of cold sores (such as itching, burning or itching).

Usual Adult Dose Herpes Simplex - mucosal/immune:

Genital herpes:

First: 1 g of valacyclovir orally twice a day for 7-10 days.

Efficacy has not been established if started more than 72 hours after symptom onset. Regular: 500 mg orally twice a day for 3 days therapy should be started at the first sign of genital herpes. Efficacy has not been established if started more than 24 hours after symptom onset.

Usual Adult Dose Herpes Simplex - Suppression:

Chronic recurrent genital herpes:
Normal immune system: 1 g of valacyclovir orally once a day.

Alternative dose with a history of disease or few recurrences per year: 500 mg orally once daily. Safety and efficacy for more than 1 year have not been established for patients.

HIV infection with CD4 100 cells/mm3 or more: 500 mg orally twice a day. Safety and efficacy beyond 6 months have not been established in HIV-infected patients. Reduced transmission of genital herpes with a history or few recurrences per year: 500 mg orally once daily for the source partner. Efficacy over 8 months has not been established in couples.

Usual Adult Dose for Herpes Zoster:

1 g of valacyclovir orally every 8 hours for 7 days
Most effective if started within 48 hours of the onset of the rash. Efficacy has not been established if started more than 72 hours after rash.

What other drugs will affect valacyclovir?

Valacyclovir can damage the kidneys, and these effects are increased when it is used with other medicines that can damage the kidneys. Before taking valacyclovir, tell your doctor if you are also using:

Lithium (Eskalith, Lithobid);

Methotrexate (Rheumatrex, Trexal);

Pain or inflammation medications such as aspirin (Anacin, Excedrin), acetaminophen (Tylenol), diclofenac (Voltaren), Etodolac (Lodine), ibuprofen (Advil, Motrin), indomethacin (Indocin), naproxen (Aleve, Naprosyn), and others;

Medicine used to treat ulcerative colitis, such as mesalamine (Pentasa) or sulfasalazine (Azulfidine);

Medicines used to prevent organ rejection, such as sirolimus (Rapamune) or tacrolimus (Prograf);

IV antibiotics such as amphotericin B (Fungizone, AmBisome, Amphotec, Abelcet), amikacin (Amikin), bacitracin (Baci-IM), capreomycin (Capastat), gentamicin (Garamycin), kanamycin (Kantrex), streptomycin, or vancomycin (Vancocin, Vancoled);

Antiviral drugs such as adefovir (Hepsera), cidofovir (Vistide), or foscarnet (Foscavir); or

Anticancer drugs such as aldesleukin (Proleukin), carmustine (BiCNU, Gliadel), cisplatin (Platinol), ifosfamide (IFEX Foundation), oxaliplatin (Eloxatin), plicamycin (Mithracin), streptozocin (Zanosar), or tretinoin (Vesanoid).

This list is not exhaustive and there may be other drugs that may interact with valacyclovir. Tell your doctor about all prescriptions and OTC medications, vitamins, minerals, herbs, and medications prescribed by other doctors. Do not start a new medicine without telling your doctor.