Drug Profile

Pregnancy Warning

No valid data are available for these drugs, as they were not tested adequately in animal studies. Use during pregnancy only for clear medical reasons. Tell your doctor if you are pregnant or thinking of becoming pregnant before you take these drugs.

Breast-feeding Warning

Acyclovir is excreted at very high levels in human milk.  Results from a study show that valacyclovir should be administered in a nursing mother with caution and only used when indicated. Because of the potential for serious adverse effects in nursing infants, you should not take these drugs while nursing.

Tell your doctor if you have or have had:

• pregnancy or are breast-feeding
• allergies to acyclovir or valacyclovir
• nerve disease
• dehydration
• bone marrow transplant
• kidney transplant
• HIV
• kidney or liver disease

Tell your doctor about any other drugs you take, including aspirin, herbs, vitamins, and other nonprescription products.

• If you plan to have any surgery, including dental, tell your doctor that you take this drug.
• Check with your doctor if there is no improvement within a few days.
• Keep affected areas clean and dry; wear loose clothing.
• Use of a condom may help to prevent transmission of herpes.

• If you miss a dose, take it as soon as you remember, but skip it if it is almost time for the next dose. Do not take double doses.
• Do not share your medication with others.
• Take the drug at the same time(s) each day.
• Take with a full glass (eight ounces) of water.
• Take with or without food.
• Take this drug for the prescribed length of time. If you stop too soon, your symptoms could come back.
• For treatment of shingles, herpes simplex, or genital herpes, start drug as soon as possible after symptoms appear.
• For treatment of chicken pox, start within 24 hours of onset of rash.
• Store at room temperature with lid on tightly. Do not store in the bathroom. Do not expose to heat, moisture, or strong light. Keep out of reach of children.

Evaluations of Drug Interactions 2003 lists no drugs, biologics (e.g., vaccines, therapeutic antibodies), or foods as causing “highly clinically significant” or “clinically significant” interactions when used together with the drugs in this section. We also found no interactions in the drugs’ FDA-approved professional package inserts. However, as the number of new drugs approved for marketing increases and as more experience is gained with these drugs over time, new interactions may be discovered.

Call your doctor immediately if you experience:

• rash or hives
• blood in urine
• confusion or hallucinations
• trembling
• abdominal pain
• lower back pain
• difficulty breathing
• decreased frequency or amount of urination
• nausea or vomiting
• loss of appetite
• chills, fever, or sore throat
• black, tarry stools
• pinpoint red spots on skin
• unusual bleeding or bruising
• chest pain
• diarrhea
• unusual thirst
• seizures
• unusual tiredness or weakness
• faintness or lightheadedness
• swelling of hands, feet, or lower legs
• changes in vision
• painful menstruation

Call your doctor if these symptoms continue:

• diarrhea
• dizziness
• headache
• joint pain
• nausea or vomiting
• acne
• trouble sleeping
• general feeling of discomfort or illness
• muscle pain
• burning, tingling, or prickling sensations
• mood or mental changes

Signs of overdose:

• coma
• nervousness or restlessness
• lower back or side pain
• decreased amount of urine
• decreased frequency of urination
• hallucinations
• seizures
• tremors

If you suspect an overdose, call this number to contact your poison control center: (800) 222-1222.

Ask your doctor which of these tests should be done periodically while you are taking this drug:

• kidney function tests (during long-term, continuous treatment)
• blood urea nitrogen and creatinine serum tests