Medications and Drugs
Pharmacy Author: Omudhome Ogbru, PharmD
Medical and Pharmacy Editor: Jay W. Marks, MD
GENERIC NAME: acyclovir
BRAND NAME: Zovirax
DRUG CLASS AND MECHANISM: Acyclovir is an antiviral drug, a synthetic
nucleoside analogue, that is active against the herpes viruses, including herpes
simplex 1 and 2 (cold sores and
genital herpes), varicella-zoster (shingles and
chickenpox), and Epstein-Barr virus (mononucleosis). Viruses take over living
cells and reproduce themselves, often at the expense of the host cell. The
acyclovir is converted to an active form by the virus itself, and the virus then
uses the active form of acyclovir rather than the nucleoside it normally uses to
manufacture DNA, a critical component of viral replication. Incorporation of
active acyclovir into new viral DNA stops the production of the DNA. Virally
infected cells absorb more acyclovir than normal cells and convert more of it to
the active form, which prolongs its antiviral activity. The FDA approved
acyclovir in March 1982.
PRESCRIPTION: Yes
GENERIC AVAILABLE: Yes
PREPARATIONS:
- 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 15-25
C (59-77 F).
PRESCRIBED FOR: Oral Acyclovir is used for treating genital herpes,
herpes zoster, 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 chicken pox 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 chicken pox 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
are 200 mg to 800 mg every 4 hours (5 times daily). The usual adult intravenous
dose is 5-10 mg/kg every 8 hours for 7 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).
PREGNANCY: There are no adequate studies of acyclovir in
pregnant
women. In a patient registry of women who used acyclovir during the first
trimester, the rate of birth defects was similar to the rate of birth defects in
the general population.
NURSING MOTHERS: Acyclovir is excreted in
breast-milk, and a
significant amount may be transferred to the infant.
SIDE EFFECTS: The most common side effects are nausea,
vomiting,
diarrhea and headache. Other reported side effects include agitation, confusion,
rash, anemia, and muscle pain. Hypersensitivity reactions,
seizures, agitation,
confusion, anemia, hepatitis, and muscle pain have also been reported.
Reference: FDA Prescribing Information
Last Editorial Review: 8/7/2008
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.
- Drug Interactions - Learn about potential drug interactions you may be exposed to. Drug interactions can occur with prescription drugs, OTC medication, vitamins, herbs, and supplements.
- Shingles - Read about shingles symptoms (contagious rash), vaccine, causes (chickenpox [varicella] virus, stress), treatment, how it's transmitted and postherpetic neuralgia.
- valacyclovir, Valtrex - Valacyclovir (Valtrex) is an antiviral drug prescribed for the treatment of herpes viruses such as shingles, genital herpes, and cold sores. Side effects, drug interactions, warnings and precautions, and patient information should be reviewed prior to taking any medication.
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