Timely antiviral treatment limits ophthalmic herpes zoster complications
Almost three-quarters of herpes zoster patients have ocular complications ranging from self-limited processes to visual loss.
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ORLANDO, Fla. Famvir (famciclovir; SmithKline Beecham) three times per day has been shown to be effective in the treatment of ophthalmic herpes zoster, a disease that affects approximately 60,000 to 120,000 people per year in the United States. This is good news for patients because Famvir offers a more convenient treatment option than previous therapies, which may help increase compliance and improve the overall management of this disease, said Alan G. Palestine, MD, a clinical associate professor of ophthalmology at Georgetown University Hospital in Washington, D.C. He reported his results of the randomized, double-masked trial here at the annual meeting of the American Academy of Ophthalmology. Obviously, the fewer times the patient has to take pills, the easier it is going to be to remember. Also, the good absorption and the long intercellular half life of Famvir, combined with the likelihood of improved compliance, should provide more stable antiviral drug levels, he told Ocular Surgery News.
The trial
In a randomized, double-masked clinical trial, 454 patients were treated for 7 days with either Famvir 500 mg three times daily or acyclovir 800 mg five times daily. All patients were enrolled in the study within 72 hours of developing lesions. The study showed that Famvir three times daily was effective in reducing eye complications associated with ophthalmic shingles, including serious complications that can lead to blindness. The study was sponsored by SmithKline Beecham.
Results for patients treated with acyclovir five times daily were comparable. Eighteen percent of acyclovir-treated patients developed keratitis, compared with 13% of Famvir patients. Decreases in visual acuity were seen in 6.3% of acyclovir-treated patients and in 2.6% of Famvir patients. Approximately 25% of patients in both groups experienced uveitis.
A safe and effective antiviral that can be used to treat ophthalmic zoster is critical in reducing a patients risk of developing serious eye complications, Dr. Palestine said. Famvir is characterized by a high rate of absorption, a long intracellular half-life and a favorable dosing regimen, which may offer an advantage over current therapies.
Famvir is the oral form of penciclovir. It has a 77% bioavailability. Famvirs long intracellular half-life in herpes virus infected cells in vitro allows for persistent antiviral activity 10 to 20 hours versus approximately 1 hour for acyclovir.
Famvir for treating herpes zoster
Famvir was generally well tolerated, according to Dr. Palestine. The most commonly reported side effects were headache and nausea. Famvir is currently approved for the treatment of acute herpes zoster in immunocompetent adults. It also is approved for the treatment or suppression of recurrent genital herpes in immunocompetent adults. Famvir is reportedly the only antiviral approved for the treatment of herpes simplex virus infections in HIV-infected individuals.
Herpes zoster, commonly known as shingles, is a viral disease characterized by an outbreak of painful and sometimes itchy blisters that may last up to several seeks and cause permanent scarring. The disease is caused by the reactivation of the varicella zoster that occurred during childhood. Although shingles can occur in anyone previously infected with the varicella zoster virus, there appear to be two general risk factors for the disease: aging and weakened immunity. If the virus reactivates in the nerves that go directly to the eye, it can cause serious eye problems, including inflammation, corneal ulcers/scarring, impaired vision and sometimes even blindness.
The study provides both a good summary of the incidence of various clinical findings, as well as a good comparison of two available drug therapies, Dr. Palestine said.
For Your Information:
- Alan G. Palestine, MD, can be reached at 1145 19th St. N.W., Ste. 500, Washington, DC 20036; (202) 833-1668; fax: (202) 833-4698. Dr. Palestine has no direct financial interest in any of the products mentioned in this article. He is a paid consultant to SmithKline Beecham.
- SmithKline Beecham can be reached at One Franklin Plaza, P.O. Box 7929, Philadelphia, PA 19101; (800) 366-8900; fax: (215) 751-7044.