- 15 mag 2019
Valtrex or the generic valacyclovir treats infection due to herpes simplex type 1 and type 2 which translates to cold sores, fever blisters and genital herpes. It also offers benefits for the skin rash of shingles or herpes zoster. Timing is critically important in both conditions. Beginning therapy for cold sores or genital herpes during the prodromal symptoms – itching, burning, tingling, numbness – prior to appearance of the lesion offers maximal benefit. Delaying onset until a day or so after the eruption guarantees lack of effect. Similarly for shingles, the window of opportunity requires instituting therapy within 72 hours of onset. Additionally Valtrex does not appear to alter the course of post-herpetic neuralgia, the lingering pain that persists for months after an attack of shingles. Valacyclovir must be converted in the body to its active form. Removal of the amino acid valine leaves acyclovir to perform the antiviral function. Blood levels of acyclovir from valacyclovir average several times greater than those resulting from taking Zovirax or acyclovir itself. Dosing for recurrent herpes simplex often involves one 500 mg pill twice daily for 3 days. An alternative regimen is 1000 mg immediately and again at 12 hours. Either seem acceptable. With shingles a higher dose of 1000 mg three times daily for 10 days seems optimal. For those with frequent recurrences of herpes simplex, a suppressive dose generally reduces the frequency of attacks. A daily dose of 500 or 1000 mg for 6 months often allows a reset. Discontinuing the drug may demonstrate a long symptom free interval. If necessary the valacyclovir may be resumed with the knowledge that with age the frequency of attacks diminishes. Unfortunately valacyclovir only reduces the frequency of clinical disease. It neither eliminates the virus from its resting place in the nerve nor does it guarantee freedom from attacks while on therapy. Reduces, yes; eliminates, no. The same applies to asymptomatic shedding of the virus and the likelihood of passage to an uninfected partner. Reduces, yes; eliminates, no. Valacyclovir rarely causes any adverse reaction and even seems safe for pregnant women where the benefits outweigh the negligible risks. Resistance of the virus to the drug appears clinically irrelevant. Valacyclovir should not be present in the circulation when a person receives the chickenpox vaccine.