Zovirax Review

Acyclovir is sold under the brand name Zovirax. It is an antiviral drug active against herpes viruses. Zovirax Ointment 5% is a formulation for topical administration. Each gram contains 50 mg of acyclovir in a polyethylene glycol base

What is Zovirax?

Zovirax (acyclovir) Ointment 5% is the first effective drug for genital herpes It is a  major therapeutic advance that was classified as a “fast track” drug for FDA review.

Why is it significant?

Zovirax represents a new era in antiviral therapy. Its unique mechanism of action allows it to attack the virus selectively with little likelihood of toxicity to the patient. It could be a prototype for other antivirals. Zovirax is the first drug safe enough for a wide variety of herpes infections.

What is the therapeutic profile?

Zovirax Ointment is indicated in the management of patients with initial herpes genitals. It is also indicated for immunocompromised patients with limited nonlife-threatening cutaneous HSV infections. In clinical trials, it decreases healing time, viral shedding, and duration of pain in these patients.

Is Zovirax effective in treating recurrent episodes of herpes?

herpes zoviraxZovirax Ointment’s indication in these conditions is limited to a decrease in viral shedding. Based on studies performed and analyzed to date, no claim is made for any effect beyond this in these conditions. The clinical significance of viral shedding has not yet been clearly defined.

Studies have shown that Zovirax hastens the elimination of HSV from established lesions of initial and recurrent genital labial infections. This decrease in viral shedding proves the antiviral effect of Zovirax.

In addition to the observed antiviral effects, clinical benefits were observed with the first episode of herpes genitals. They were also observed in immunocompromised patients with either initial or recurrent herpes genitalis and herpes labialis. However, in normal patients, infections are characteristically of shorter duration and less severe. Therefore, the use of the topical ointment relatively late in these patients did not show a significant reduction in clinical signs or HSV symptoms, even though an antiviral effect was demonstrated.

What is the mechanism of action?

Zovirax normally exists in its inactive form. It is preferentially taken up and selectively converted to its active form by the herpes virus-infected cell. This conversion does not occur to any significant degree in normal cells.

Once Zovirax is activated in the HSV-infected cell, it interferes with the synthesis of viral DNA. Thus, it inhibits viral replication. Simplistically, the virus commits suicide by activating and converting Zovirax to a form that is toxic to the virus itself. Because of this unique mechanism of action, it’s is an extremely well-tolerated product.

How can it be so effective and yet so well tolerated?

Zovirax is virtually inactive in normal cells. It becomes biologically active to a significant degree only in virus-infected cells. This is because it needs the presence of herpes enzymes to work. The herpes virus enzyme, thymidine kinase, initiates the conversion of Zovirax to stop the replication of the virus. This means that it is able to fight the virus with little damage to normal body cells. And there is little likelihood of toxicity for patients.

Is Zovirax a “cure” for herpes infections?

No. It has no effect on the latent virus in the nerve ganglion. It stops the production of the virus once the virus starts to replicate.

What is the side effect profile?

A. In all studies, there was no significant difference between the drug and the placebo in the reported adverse reactions. Nor were there any differences in abnormal clinical laboratory findings. Because ulcerated lesions are characteristically sensitive to contact, patients may experience discomfort upon application of the ointment.

In controlled clinical trials, mild pain (including transient burning and stinging) was reported by Drs. Corey and Holmes to be “more frequent with first episodes of genital herpes (29%) than with recurrent episodes (6%) and is more frequent in women (36%) than in men (8%). Topical acyclovir in polyethylene glycol is not approved for intravaginal use; the polyethylene glycol base may cause vaginal erythema.” Less frequent reactions included pruritus, rash, and vulvitis.

Does Zovirax interact with other drugs?

Clinical experience has identified no interactions resulting from the concomitant use of topical Zovirax with other drugs.

What about contraindications, warnings or precautions?

Zovirax Ointment 5% is contraindicated in those patients who develop hypersensitivity or chemical intolerance to the components of the formulation. It is intended for cutaneous use only and should not be used in the eye.

The recommended dosage, frequency of applications, and length of treatment should not be exceeded. There exists no data that demonstrate that the use of Zovirax Ointment will prevent transmission of infection to other persons. Nor will it prevent recurrent infections when applied in the absence of signs and symptoms.

Acyclovir is classified in Pregnancy Category C. It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

What is the recommended dosage?

Zovirax Ointment 5% should be applied in sufficient quantity to adequately cover all lesions. Do this every three hours, six times per day. Drs. Corey and Holmes in the Annals of Internal Medicine recommend “an application of all external genital lesions four to six times daily for 7 to 14 days, or until all lesions have crusted.

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Although the duration of therapy used in clinical trials is 7 days, a longer course of therapy may prevent new lesions. We do not recommend routine use of [Zovirax] in patients with recurrent genital herpes. However, early application of ointment in those episodes of recurrent disease involving large lesion areas (50 to 150 mm’) may have the slight benefit to male patients. A finger cot or rubber glove should be used when applying Zovirax to prevent autoinoculation of other body sites and transmission of infection to other persons.

How is the drug supplied and how much will it cost?

Zovirax Ointment 5% is supplied in 15g tubes with each gram containing 50mg of acyclovir in a polyethylene glycol base. It should be stored at 15°C to 25°C (59°F to 78°F) in a dry place. It will cost the patient upon prescription approximately $18-$21.

How many episodes of herpes will a single tube treat?

The amount of Zovirax in a 15g tube should be more than adequate to treat a case of initial herpes.

The above will give you some idea of how unique the drug acyclovir is. The intravenous infusion formulation is available now and the oral capsule form is expected sometime in 1983. An ophthalmic ointment is under development.

Some people wonder why reduced viral shedding is necessary. Acyclovir does reduce the time of viral shedding and this is important. The less time virus is given off from the lesion the less likely a person is to spread the disease. Acyclovir appears to be most useful for those individuals who manifest genital herpes disease symptoms for the first time. The clinical trials show a decrease in healing time and viral shedding in both men and women. The person standing to gain the most benefit will be the exposed partner who develops signs and symptoms and consults with a physician early in the infection.

None of the clinical studies have given conclusive proof that acyclovir will prevent the virus from going into the latent stage. Even with the early application of the drug. Since acyclovir cannot be counted on to prevent the latent infection stage, it follows that recurrent herpes infections will not be prevented either.

If you plan a purchase of Zovirax and price is a consideration, you might try calling several pharmacies in your area for price comparisons. The difference can be substantial in some areas. While in the drugstore be sure to purchase some finger cots or surgical rubber gloves with which to apply the ointment.

Intravenous Zovirax Facts

The following question and answer section is to acquaint you with the latest form of acyclovir—intravenous Zovirax.

How will intravenous Zovirax be used?

Intravenous Zovirax is a systemic treatment for serious HSV-1 and HSV-2 infections in hospitalized patients. It is approved for initial and recurrent HSV infections in adults and children. Specifically, whose natural defenses against infection are impaired, including cancer patients and organ transplant patients.

What therapeutic benefits does intravenous Zovirax offer?

Intravenous Zovirax speeds healing, reduces pain and stops the HSV from replicating. In immune-normal patients, the HSV usually causes painful, recurring genital sores or cold sores. In immune-suppressed patients, HSV infections can spread to vital organs and be fatal.

How does intravenous it work?

Zovirax attacks the virus selectively, leaving uninfected cells virtually unharmed. The drug becomes biologically active in virus-infected cells, where it is converted to its active form by a virus enzyme. In this form, Zovirax prevents the virus from replicating and spreading to other cells. By stopping virus replication, Zovirax speeds healing and reduces pain.

Is intravenous Zovirax a treatment or a cure?

Zovirax is used to manage active herpes virus infections. During the initial infection, the virus takes up residence in certain nerve cells. It remains in the body in latent (inactive) form. Occasionally, the latent virus becomes active and causes recurrent outbreaks. There is no present evidence that Zovirax will eliminate the latent virus from the body. But when the virus begins actively replicating, Zovirax attacks it and controls its spread. In this sense, herpes infections are similar to hypertension, diabetes and many other diseases, which are not “cured” but managed with medications.

Does intravenous Zovirax prevent recurrent herpes infections?

Studies are underway to determine whether it might be useful in preventing HSV infections in high-risk, immune-suppressed patients. Until these data are reviewed, it is not known whether intravenous Zovirax will be indicated for this use.

Can intravenous Zovirax be used to treat shingles?

Clinical studies are underway to test the use of intravenous Zovirax in a number of diseases caused b viruses in the herpes family, including shingles, which caused by varicella zoster virus. However, Zovirax is not approved for this indication. Until these data are reviewed, it is not known whether Zovirax will be indicated for shingles.

Is it available over the counter?

Because Zovirax IV is administered by intravenous“ infusion, its major use will be for hospital patients. Zovirax Ointment is available on prescription for the management of if less serious HSV infections. Zovirax Ointment is indicated for initial infections of genital herpes and for localized HSV-1 and HSV-2 infections of the skin of immune-suppressed patients

This is the treatment for herpes as we currently know it. The drug should shorten the course of an episode of herpes, but it is not a cure. You should take particular note that to another. It is unhealthy and can be dangerous to treat herpes or any other disease improperly. Do not believe everything the media presents to you. It seems a week goes by that a “cure” for herpes doesn’t make the news. Be careful. Learn about herpes complications.

Summary
Zovirax - What It Is and How It Works
Article Name
Zovirax - What It Is and How It Works
Description
Zovirax (acyclovir) Ointment 5% is the first effective drug for genital herpes, a sexually-transmitted disease that afflicts up to 20 million people in the United States. It is a breakthrough antiviral drug discovered and developed by Burroughs Welcome Co.
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