Proper Use

Drug information provided by: Merative, Micromedex®

Patient information about the treatment of herpes, chickenpox, or shingles is available with this medicine. Read it carefully before using this medicine.

Acyclovir is best used as soon as possible after the symptoms of herpes infection or shingles (for example, pain, burning, blisters) begin to appear.

If you are taking acyclovir for the treatment of chickenpox, it is best to start taking acyclovir as soon as possible after the first sign of the chickenpox rash, usually within one day.

Acyclovir capsules, tablets, and oral suspension may be taken with meals or on an empty stomach.

Acyclovir is best taken with a full glass (8 ounces) of water.

If you are using acyclovir oral suspension, use a specially marked measuring spoon or other device to measure each dose accurately. The average household teaspoon may not hold the right amount of liquid.

To help clear up your herpes infection, chickenpox, or shingles, keep taking acyclovir for the full time of treatment, even if your symptoms begin to clear up after a few days. Do not miss any doses. However, do not use this medicine more often or for a longer time than your doctor ordered.

If you are taking acyclovir capsules, tablets, or oral suspension, you should drink plenty of water to avoid becoming dehydrated.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage forms (capsules, oral suspension, or tablets):
    • For treatment of genital herpes:
      • Adults and children 12 years of age and older—200 milligrams (mg) five times a day for ten days.
      • Children up to 12 years of age—Use and dose must be determined by the doctor.
    • For prevention of recurrent outbreaks of genital herpes infections:
      • Adults and children 12 years of age and older—200 to 400 mg two to five times a day for five days or up to twelve months, depending on how often your outbreaks of infection occur.
      • Children up to 12 years of age—Use and dose must be determined by the doctor.
    • For treatment of chickenpox:
      • Adults and children who weigh over 88 pounds (40 kilograms)—800 mg four times a day for five days.
      • Children 2 years of age and older and weighing 88 pounds (40 kilograms) or less—Dose is based on body weight and must be determined by the doctor. The usual dose is 20 mg per kilogram (kg) of body weight, up to 800 mg, four times a day for five days.
      • Children up to 2 years of age—Use and dose must be determined by the doctor.
    • For treatment of shingles:
      • Adults and children 12 years of age and older—800 mg five times a day for seven to ten days.
      • Children up to 12 years of age—Use and dose must be determined by the doctor.
  • For injection dosage form:
    • For treatment of herpes of the brain, genitals, or mucous membranes, or for the treatment of shingles:
      • Adults and children 12 years of age and older—Dose is based on body weight and must be determined by the doctor. The usual dose is 5 to 10 mg of acyclovir per kg (2.3 to 4.5 mg per pound) of body weight, injected slowly into a vein over at least a one-hour period, and repeated every eight hours for five to ten days.
      • Children up to 12 years of age—Dose is based on body weight and must be determined by the doctor. The usual dose is 10 mg to 20 mg of acyclovir per kg (4.5 mg to 9.1 mg per pound) of body weight, injected slowly into a vein over at least a one-hour period and repeated every eight hours for seven to ten days.
    • For treatment of widespread herpes virus infection in newborns:
      • Infants from birth to 3 months of age—Dose is based on body weight and must be determined by the doctor. The usual dose is 10 mg of acyclovir per kg (4.5 mg per pound) of body weight, injected slowly into a vein over at least a one-hour period and repeated every eight hours for ten days.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Portions of this document last updated: Feb. 01, 2024

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