The main drugs being developed to work against the herpes simplex virus (HSV) are antiviral agents called nucleoside and nucleotide analogues, that block viral reproduction. They include acyclovir (Zovirax), valacyclovir (Valtrex), famciclovir (Famvir).

The antiviral drugs available in pill form were developed specifically for the treatment of genital herpes. Of antivirals in May greatly reduce the severity of an outbreak primary and reduce the time needed genital herpes outbreaks to heal. The drug also reduces the number of days of painful symptoms and for some people, the number of days you can spread the virus. Antiviral drug is most effective if taken when you first notice the prodromal symptoms (tingling and pain) of a genital herpes outbreak applicant and if they are adopted for the next 5 to 7 days or until symptoms disappear. Some people with frequent recurrent episodes (more than 6 relapses a year) to take the antiviral drugs every day (suppressive therapy) to help reduce the frequency and duration of recurrent outbreaks.

Brief history
Aciclovir (make Zovirax) is the oldest of antivirals. It ‘been available since 1982 in a form of topical (as an ointment) and sold since 1985 in the form of pill. Aciclovir is now available in a generic form.

Valtrex (valacyclovir) was the second antiviral drug to come to market in the United States, and was approved by the FDA in December 15, 1995. Valtrex is manufactured by GlaxoSmithKline. Valtrex is a prodrug of acyclovir, which means that the body converts into acyclovir after it has been absorbed. This drug acyclovir provides more efficiently so that the body absorbs most of the drug, which has the advantage of taking the medicine fewer times during the day.

Canadian Famvir (famciclovir) is a prodrug manufactured by Novartis. When hired, the body converts it to the long-acting antiviral drug penciclovir. How valacyclovir, is well absorbed, persists for a longer time in the body, and can be taken less frequently than acyclovir.

Mechanism of action
Antiviral agents reduce viral replication by inhibiting the synthesis of viral DNA needed to reproduce itself. This helps keep the virus inactive. Directions and approved uses

Aciclovir is indicated for:

initial treatment episodes and management of recurrent episodes of genital herpes
treatment of acute herpes zoster (shingles)
treatment of varicella (chickenpox)
Valacyclovir is indicated for:

the treatment or suppression of genital herpes and for the suppression of genital herpes applicant
reducing transmission of genital herpes
treatment of herpes zoster
treatment of cold sores (herpes labialis)
Famciclovir is indicated for:

the treatment or suppression of genital herpes applicant
treatment of acute herpes zoster
Effectiveness
Clinical studies have not found significant differences in effectiveness between the three drugs. All are quite safe, very rarely produce any side effects at all. For the first treatment of genital herpes infections, oral or acyclovir valacyclovir is preferable famciclovir. The effectiveness of famciclovir initial episode of genital herpes infection has not been established.

Endovenosa acyclovir is used to treat severe flare-ups or outbreaks that effect internal organs.

Side effects and adverse side effects
All these agents are well tolerated and are excellent security. Possible side effects from oral agents include nausea, vomiting, headache, fatigue, tremor, and very rarely, seizures. They may effect the kidney, however, and people with kidney problems should use them with caution and in lower doses. Administration intravenous increases the risk of kidney problems and may cause blood clots at the injection site. In rare cases, can cause central nervous system complications.

Pharmacokinetics
Zovirax generic has poor bioavailability of approximately 20% and a short half-life, which requires frequent dosing. Aciclovir speed healing of injuries and suppress viral shedding if taken within 24 hours after the first indication of a recurrent episode. Early treatment can also prevent the development of injury in some patients.

Valacyclovir provides a unique mechanism to improve the oral bioavailability of the compound, acyclovir. Valtrex cheap is a prodrug converted into acyclovir in the liver and intestine. He has better bioavailability (approximately 55%) and has a duration of action of acyclovir. Thus, valacyclovir requires less frequent dosing of acyclovir. Valacyclovir is most effective if taken within 24 hours the first signs of an outbreak.

Famciclovir is a prodrug for the active metabolite penciclovir. Famciclovir is converted into compounds for its active inside the cell infected by contact with an enzyme for the virus. What has raised the bioavailability of 77%. It remains active in the body longer than acyclovir (half the dose is still active after 10 to 20 hours) and, as valacyclovir, requires less frequent dosing (usually two or three times a day). It is most effective if taken within six hours of onset of symptoms.

Both Famciclovir and valacyclovir have a greater bioavailability oral acyclovir. Famciclovir and valacyclovir, which are better absorbed by the body, can be taken less often Zovirax online. The draft simplification of the frequency of administration of famciclovir and valacyclovir, allows patients more convenient dosing regimens with less disruption of their activities of daily life.