May 28, 2017
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How Supplied


Indications And Clinical Use

ZOVIRAX® (acyclovir) is indicated for the following conditions:

  • The treatment of initial episodes of herpes genitalis.
  • The suppression of unusually frequent recurrences of herpes genitalis (6 or more episodes per year).
  • The acute treatment of herpes zoster (shingles) and varicella (chickenpox).

The results of clinical studies suggest that some patients with recurrent genital herpes may derive clinical benefit from the administration of oral ZOVIRAX® if taken at the first sign of an impending episode. Those most likely to benefit are patients who experience severe, prolonged recurrences; such intermittent therapy may be more appropriate than suppressive therapy when these recurrences are infrequent.

Early treatment of acute herpes zoster (shingles) in immunocompetent individuals with oral ZOVIRAX® resulted in decreased viral shedding; decreased time to healing; less dissemination; and alleviation of acute pain.

Treatment of varicella (chickenpox) in immunocompetent patients with oral ZOVIRAX® reduced the total number of lesions, accelerated the progression of lesions to the crusted and healed stages, and decreased the number of residual hypopigmented lesions. In addition, ZOVIRAX® decreased fever and constitutional symptoms associated with chickenpox.

The prophylactic use of acyclovir in chickenpox has not been established.

Geriatrics ( ≥ 65 Years of Age): Use in the geriatric population may be associated with differences in safety due to age-related changes in renal function and a brief discussion can be found in the appropriate sections (see WARNINGS AND PRECAUTIONS).

Pediatrics ( < 2 Years Old): No data are available.


Dosing Considerations

  • The dosage of ZOVIRAX® (acyclovir) should be reduced in patients with impaired renal function.
  • Therapy should be initiated as soon as possible after a diagnosis of chickenpox or herpes zoster, or at the first sign or symptoms of an outbreak of genital herpes.
  • The recommended dose and duration of use is dependent on the indication.

Recommended Dose And Dosage Adjustment

Treatment of Initial Infection of Herpes Genitalis: 200 mg (one 200 mg tablet or one teaspoonful of suspension [5 mL]) every 4 hours, 5 times daily for a total of 1 g daily for 10 days. Therapy should be initiated as early as possible following onset of signs and symptoms.

Suppressive Therapy for Recurrent Herpes Genitalis

The initial recommended dose is 200 mg (one 200 mg tablet or one teaspoonful of suspension [5 mL]) three times daily. This can be increased if breakthrough occurs up to a dosage of one 200 mg tablet or one teaspoonful [5 mL] of suspension, five times daily. If necessary, a dose of 400 mg (two 200 mg tablets or two teaspoonfuls of suspension [10 mL]) given twice daily may be considered. Periodic re-evaluation of the need for therapy is recommended.

Administration of ZOVIRAX® for intermittent therapy is 200 mg (one 200 mg tablet or one teaspoonful [5 mL] of suspension) every 4 hours 5 times daily for 5 days. Therapy should be initiated at the earliest sign or symptom (prodrome) of recurrence.

Treatment of Herpes Zoster

800 mg of oral ZOVIRAX®, every 4 hours, 5 times daily for 7 to 10 days. Treatment should be initiated within 72 hours of the onset of lesions. In clinical trials, the greatest benefit occurred when treatment was begun within 48 hours of the onset of lesions.

Treatment of Chickenpox

20 mg/kg (not to exceed 800 mg) orally, 4 times daily for 5 days. Therapy should be initiated within 24 hours of the appearance of rash.

Patients With Acute or Chronic Renal Impairment

Caution is advised when administering acyclovir to patients with impaired renal function. Adequate hydration should be maintained.

Comprehensive pharmacokinetic studies have been completed following intravenous acyclovir infusions in patients with renal impairment.

Based on these studies, dosage adjustments are recommended in Table 5 for genital herpes and herpes zoster indications.

Table 5 : Dosage Modification for Renal Impairment

Normal Dosage Regimen Creatinine Clearance (mL/min/1.73m²) Adjusted Dosage Regimen
Dose (mg) Dosing Interval (hours)
200 mg every 4 hours > 10 200 every 4 hours, 5 x daily
0-10 200 every 12 hours
400 mg every 12 hours > 10 400 every 12 hours
0-10 200 every 12 hours
800 mg every 4 hours > 25 800 Every 4 hours, 5 x daily
10-25 800 every 8 hours
0-10 800 every 12 hours


For patients who require hemodialysis, the mean plasma half-life of acyclovir during hemodialysis is approximately 5 hours. This results in a 60% decrease in plasma concentrations following a six-hour dialysis period. Therefore, the patient's dosing schedule should be adjusted so that an additional dose is administered after each dialysis.

Peritoneal Dialysis

No supplement dose appears to be necessary after adjustment of the dosing interval.

Missed Dose

If a dose of ZOVIRAX® is missed, the patient should be advised to take it as soon as he/she remembers, and then continue with the next dose at the proper time interval.


Storage And Stability

ZOVIRAX® Tablets should be stored at controlled room temperature (15 to 25°C) in a dry place and protected from light.

ZOVIRAX® Suspension should be stored at controlled room temperature (15 to 25°C).

Dosage Forms, Composition And Packaging

Suspension: Each teaspoonful (5 mL) of ZOVIRAX® Suspension contains 200 mg acyclovir and the non-medicinal ingredients banana flavour, cellulose, glycerin, methylparaben, propylparaben, sorbitol, vanillin, and water.

Tablets: Each ZOVIRAX® 200 Tablet contains 200 mg acyclovir and the non-medicinal ingredients cellulose, indigotine, lactose, magnesium stearate, povidone, and sodium starch glycolate.

ZOVIRAX® Suspension is available in bottles of 125 mL* and 475 mL. Each teaspoonful (5 mL) of off-white, banana-flavoured suspension contains 200 mg acyclovir.

*125 mL bottle not available in Canada

ZOVIRAX® 200 Tablets are available in bottles of 100 tablets. Each blue, shield-shaped, bevel-edged, compressed tablet contains 200 mg acyclovir, and is imprinted with “ZOVIRAX” on one side and a triangle on the reverse.

GlaxoSmithKline Inc., 7333 Mississauga Road, Mississauga, Ontario, L5N 6L4 1-800-387-7374. Revised: November 10, 2014

This monograph has been modified to include the generic and brand name in many instances.

Last reviewed on RxList: 1/7/2016

How Supplied

Zovirax - User Reviews

Zovirax User Reviews

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