Valtrex.

Valtrex (valacyclovir) is a prescription drug intended for the treatment of infections caused by the herpes virus – such as shingles and genital herpes. Your health care provider may also prescribe Valtrex for some other conditions and you will need to take it exactly as recommended to make sure you are benefitting from the treatment as much as possible. Tell your doctor if you are taking any medications known to cause interactions with Valtrex – such as methotrexate, drugs used to prevent organ transplant rejection, IV antibiotics, medicines used to treat ulcerative colitis, antiviral medicines, pain or arthritis medicines, lithium, cancer medicines, and any other products you purchase online or at your local pharmacy. Some medical conditions you have may require a dose adjustment, so you will need to notify your health care provider of the fact of having liver disease, acquired immunodeficiency syndrome, problems with your immune system, human immunodeficiency virus infection, or kidney disease. Mild side effects are possible and can include headache, constipation, vomiting, upset stomach, diarrhea or loose stools.