An antiviral drug named Zovirax is a synthetic nucleoside analogue and it 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). Virus takeover living cells of the host and they reproduce themselves. The virus itself converts the Zovirax into an active form. Then the active form of Zovirax is used by the virus rather than the nucleoside. The nucleoside used to manufacture the DNA which is a critical component of viral replication. Due to incorporation of active Zovirax into the virus, the production of DNA is stopped. Zovirax was approved by the FDA in the year 1982.
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
15-25 C (59-77 F) is the required temperature to store Zovirax.
Prescribed for
Zovirax is taken orally. It is prescribed for the treatment of the genital herpes, herpes zoster and the chickenpox. The pain and number of lesions in the initial case of genital herpes is reduced by Zovirax and it also decreases the frequency and severity of recurrent infections. Zovirax reduces pain, shortens the healing time and limits the spread of virus and the formation of new lesions during the treatment of shingles. Chickenpox can be treated using Zovirax and it acts to reduce healing time and limits the number of lesions and if used within 24 hours. It reduces fever after the onset of illness. Treatment of herpes simplex and chickenpox in immune-compromised patients is done by Intravenous Zovirax. Typically to treat initial genital herpes, Zovirax ointment is used. It has been shown to decrease pain, limit the spreading of the infection and reduce healing time.
Dosage
The intake of Zovirax can be done with or without food. The oral doses for adult are 200mg to 800mg every 4 hours (5 times daily). 5-10mg/kg every 8 hours for 7 days is the usual intravenous dose for an adult.
Overdosing
Agitation, coma and seizures are some of the signs of Zovirax overdose.
Drug interaction
Decrease in levels of phenytoin (Dilantin) or valproic acid (Elavil, Elavil ER) may be caused due to Zovirax. Serum levels of theophylline (TheoDur, Respbid, SloBid, Theo24, Theolair, Uniphyl, SloPhyllin) may be increased by Zovirax.
Pregnancy
The data about Zovirax reaction on pregnant women is very insufficient. With the existing data available, it is very difficult to come to a conclusion. This is because the rate of birth defects was noticed very similar to the rate of defects in general population. The patient registry of women who used Zovirax during the first trimester did not give any side effects. Zovirax is considered pretty safe for women during the time of their pregnancy
Nursing mothers
Excretion of Zovirax takes place from breast milk from which a significant amount may be transferred to the infant. You might need to consult your doctor before you decide to breast feed the instant.
Side effects
Nausea, vomiting, headache and diarrhea are the most common side effects of Zovirax. Agitation, confusion, anemia, hepatitis, hypersensitivity reactions, seizures, rash and muscle pain are other side effects that have also been reported.