Generic name: Acyclovir.

Zovirax is an antiviral. It is the only orally administered drug that can reduce the rate of growth of the herpes virus and its relatives.

Quick Facts About Zovirax


Used to treat certain infections with herpes viruses including genital herpes, shingles, and chicken pox. Zovirax ointment is used to treat initial episodes of genital herpes and certain herpes simplex infections of the skin and mucous membranes.

Zovirax Dosage

Should not exceed prescribed dose, nor share medication with others. Avoid eye exposure to ointment. Use rubber glove or finger cot to protect against spreading infection.

  • Usual adult dose: for genital herpes — one 200-milligram capsule or 1 teaspoonful of liquid every 4 hours, taken 5 times per day for 10 days. If herpes is recurrent, dose is 400 milligrams (two 200-milligram capsules or 2 teaspoonfuls) taken 2 times per day for up to 12 months. If herpes is intermittent, dose is one 200-milligram capsule or I teaspoonful of liquid every 4 hours, taken 5 times per day for 5 days. Ointment — apply to affected area every 3 hours, 6 times per day, for 7 days. For herpes shingles — 800 milligrams (four 200-milligram capsules, two 400-milligram tablets, or 4 teaspoonfuls of liquid) every 4 hours, 5 times per day for 7 to 10 days. If you have kidney disorder —- doctor will adjust dose.
  • Usual child dose: 20 milligrams per 2.2 pounds of body weight, taken orally 4 times per day for 5 days. Maximum dose is 800 milligrams per day. Not generally prescribed for children under 2 years.
  • Missed dose: take as soon as possible, unless almost time for next dose. In that case, do not take missed dose; go back to regular schedule. Do not double doses. Apply missed ointment dose as soon as you remember, then continue your regular schedule.

Zovirax Side Effects

Overdose symptoms:

Zovirax is generally safe; how ever, overdose may lead to kidney damage. If you suspect an overdose, immediately seek medical attention.

More common side effects: confusion, constipation, diarrhea, dizziness, fever, fluid retention, general feeling of bodily discomfort, gland enlargement in the groin, hair loss, hallucinations, headache, hives, itching, muscle pain, nausea, pain, skin rash, sleepiness, stomach and intestinal problems, visual abnormalities, vomiting. Common side effects of Zovirax ointment: burning, itching, mild pain, skin rash, stinging, vaginal inflammation.

Less common  or rare Zovirax side effects: abdominal pain, anaphylaxis (severe allergic reaction), diarrhea, dizziness, fatigue, gas, headache, inability to sleep, leg pain, loss of appetite, medicinal taste, rash, retention of fluid, sore throat, tingling or pins and needles, vomiting, weakness.


Inform your doctor before combining Zovirax with:

cyclosporine (Sandimmune), interferon (Roferon), probenecid (Benemid), zidovudine (AZT/Retrovir).

No known food/other substance interactions.

Special Cautions

If pregnant or planning to become pregnant, inform your doctor immediately. May appear in breast milk; could affect a nursing infant.

Seniors with reduced kidney function should take a lower oral dosage.

Not generally prescribed for children under 2 years. Follow doctor’s instructions for children 2 years and older.

  • This medication should not be taken if you have experienced an allergic reaction to it or similar drugs.
  • If you are being treated for a kidney disorder, consult with your doctor before taking Zovirax.
  • Decreased sperm count has been observed in animals given high doses of Zovirax; however, this effect has not been documented in humans.


HealthSurvey.org provides accurate and independent information prescription pills, over-the-counter medicines and natural products. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment. If you have questions about  dosage, or Zovirax side effects, please contact your healthcare provider