acyclovir, Zovirax (cont.)

Pharmacy Author:
Medical and Pharmacy Editor:
Medical and Pharmacy Editor:




  • Capsules: 200 mg.
  • Tablets: 400 and 800 mg.
  • Suspension: 200 mg/5 ml.
  • Injection: 50 mg/ml.
  • Powder for injection: 500 and 1000 mg.
  • Ointment: 5%.

STORAGE: Acyclovir should be stored at room temperature, between 15 C 25 C (59 F to 77 F).

PRESCRIBED FOR: Oral acyclovir is used for treating genital herpes, shingles, and chickenpox.

Acyclovir reduces the pain and the number of lesions in the initial case of genital herpes, and decreases the frequency and severity of recurrent infections.

In the treatment of shingles, acyclovir reduces pain, shortens the healing time, and limits the spread of virus and the formation of new lesions.

Acyclovir can be used to treat chickenpox and acts to reduce healing time, limit the number of lesions, and reduce fever if used within the first 24 hours after the onset of illness.

Intravenous acyclovir is used for treating herpes simplex and chickenpox in immuno-compromised patients and severe genital herpes.

Acyclovir ointment is used topically to treat initial genital herpes where it has been shown to decrease pain, reduce healing time, and limit the spread of the infection.

DOSING: Acyclovir may be taken with or without food.

  • Adult oral doses for treating genital herpes are 200 mg every 4 hours (5 times daily) for 7-10 days or 400 mg three times daily for 5-10 days.
  • Herpes Zoster (shingles) is treated with 800 mg every 4 hours (5 times daily) for 7 to 10 days.
  • The dose for treating chicken pox is 800 mg 4 times daily. The usual adult intravenous dose is 5-10 mg/kg every 8 hours for 7-10 days.

DRUG INTERACTIONS: Acyclovir may decrease levels of phenytoin (Dilantin) or valproic acid (Depakote, Depakote ER). Probenecid (Benemid) may increase acyclovir serum levels by decreasing renal excretion of acyclovir. Acyclovir may increase serum levels of theophylline (Theo-Dur, Respbid, Slo-Bid, Theo-24, Theolair, Uniphyl, Slo-Phyllin).

Medically Reviewed by a Doctor on 3/27/2015

Report Problems to the Food and Drug Administration

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Pill Finder Tool

Need help identifying pills and medications?
Use the pill identifier tool on RxList.

Back to Medications Index