Valtrex (valacyclovir hydrochloride) is FDA approved for the treatment of herpes simplex (cold sores and genital herpes) and varicella zoster virus (chickenpox and shingles). It is an antiviral agent in a class called DNA polymerase inhibitors. These two viruses are closely related and are quite prevalent in the U.S. with an estimated 45 million people, 12 years and above infected with herpes simplex virus alone. This is particularly important in view of the concurrent HIV/AIDS epidemic. The fact is that sores caused by the herpes simplex viruses facilitate HIV transmission, and HIV infection encourages drug resistance and more severe disease scenarios in herpes simplex infections.
How Valtrex Works
Herpes simplex viruses and varicella zoster viruses are DNA viruses that carry their own genetic material. When they infect a human cell, they hijack it producing viral genetic material and other proteins and enzymes that are reassembled into new infective viruses and released.
Valtrex is metabolized in the intestines and/or the liver to acyclovir, its active form in the body. This form is an analogue (look alike) of one of the metabolites used in assembling the chains of viral genetic material. It interferes with the enzyme responsible for this assembly, DNA polymerase. The same hijacking process makes the viral DNA polymerase much more susceptible to Valtrex than the host DNA polymerase. Another viral enzyme, thymidine kinase, greatly enhances the effects of Valtrex. The overall effect is the blocking of the viral DNA polymerase from picking the genuine metabolites for its function, total paralysis of the enzyme, stopping the production of viral DNA, hence shutting down viral replication.
Clinical Effects of Valtrex
The pains associated with the lesions of herpes simplex virus infections as seen in genital herpes and cold sores, respond well to Valtrex. The lesions heal faster on the medication and recurrence rates are reduced. Above all, transmission rates, even between couples, are significantly reduced on Valtrex.
The same improvements are seen in varicella virus infections, with severity reduction in chickenpox, and reduction in duration and intensity of pain and lesions in herpes zoster (shingles).