Acyclovir
(ZOVIRAX®)
Indication
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).
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
Dosages & Administration
- 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.
Hemodialysis
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.
Side Effect
Zovirax (acyclovir) is a synthetic nucleoside analogue that interferes
with the replication of herpes viruses. Zovirax is used to treat
shingles, chickenpox, and genital herpes. Acyclovir is the name of the
available generic. Side effects of Zovirax include nausea, vomiting,
diarrhea, loss of appetite, stomach pain, headache, feeling lightheaded,
swelling in your hands and feet, and malaise.Zovirax tablets are available in 200, 400 and 800 mg strengths and as a liquid suspension with 200 mg strength per 5 ml. Usual doses are 800 mg every 4 hours, 5 times a day for 10 days for shingles; doses for genital herpes infection are the same interval but start with 200 mg. Doses for chickenpox is the same as shingles except it goes for only 5 days for adults; for children ages 2 and up are weight based (20 mg per Kg) up to 40 Kg, 5 times a day for 5 days. Over 40 Kg, the person gets the adult dose for 5 days. Serious side effects of Zovirax include renal function problem. There are no good studies on pregnant women. Zovirax may be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Caution is advised with use of Zovirax in women who are breastfeeding since the drug is secreted in breast milk. Safety and efficacy has not been studied in pediatric patients below the age of 2 years.
Our Zovirax Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to