Valtrex is used to treat herpes zoster (shingles) and genital herpes. It does not cure herpes infections but decreases pain and itching, helps sores to heal, and prevents new ones from forming.

This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

Valtrex 500 Mg Merck & Co Special precautions

Before taking valtrex,

• Tell your doctor and pharmacist if you are allergic to acyclovir (Zovirax), valtrex, or any other drugs.

• Tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially cimetidine (Tagamet), probenecid (Benemid), and vitamins.

• Tell your doctor if you have or have ever had kidney or liver disease, problems with your immune system, human immunodeficiency virus infection (HIV), or acquired immunodeficiency syndrome (AIDS).

• Tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking valtrex, call your doctor.

Valtrex 500 Mg Merck & Co Side effects of Valtrex

Although Valtrex 500 Mg Merck & Co Side effects from valtrex are not common, they can occur. Tell your doctor if any of these symptoms are severe or do not go away:

• headache

• upset stomach

• vomiting

• diarrhea or loose stools

• constipation

If you experience any of the following Valtrex 500 Mg Merck & Co Side effects, call your doctor immediately:

• rash

• itching

• confusion

• yellowness of the skin or eyes

• fever

• blood in the urine

Keep all appointments with your doctor and the laboratory.

Do not have sexual intercourse when you can see the genital herpes lesions. However, genital herpes can be spread even when there are no symptoms.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.