Valtrex 500mg , is an antiviral drug used in the management of herpes simplex, herpes zoster(shingles), and herpes B. It is a prodrug, which is converted to acyclovir in a person’s body. Valtrex 500mg was approved for medical use in 1995. . Valtrex 500mg has been available as a generic drug in the U.S. since November 25, 2009 Valtrex 500mg involves an active composition like valacyclovir that are pharmacologically classified as nucleoside analogue of viral DNA polymerase prohibitor.
Valtrex indicated for
Varicella zoster virus (VZV) infections – herpes zoster
Valtrex 500mg tablets are used to treat of herpes zoster (shingles) and ophthalmic zoster in immunocompetent adults. Valaciclovir tablets are used to treat of herpes zoster in adult patients with mild or moderate immunosuppression.
Herpes simplex virus (HSV) infections
Valaciclovir tablets are necessary for the treatment and suppression of HSV infections of the skin and mucous membranes including In immunocompetent adults and adolescents and in immunocompromised adults the Valtrex indicated for first episode of genital herpes Indicated for recurrences of genital herpes in immunocompetent adults and adolescents and in immunocompromised adults Suppression of recurrent genital herpes in immunocompetent adults and adolescents and in immunocompromised adults. treatment and suppression of recurrent ocular HSV infections
Cytomegalovirus (CMV) infections:
Valaciclovir tablets are indicated for the prophylaxis of CMV infection and disease following solid organ transplantation in adults and adolescents
PHARMACOLOGICAL ACTION OF VALTREX 500MG
Valacyclovir is a prodrug which is go through phosphorylation by using viral thymidine kinase enzyme for convert of acyclovir triphosphate, an active metabolite.
This active molecule is included in the prohibition of herpes viral DNA replication by aggressive prohibition of viral DNA polymerase.
After infusion of this metabolite into the virus & leads to terminate the developing viral DNA chain. Valacyclovir consist of; Block the DNA synthesis Destabilizing the strand Prevention of new viral growth
After Valtrex 500mg oral intake , valacyclovir is fastly absorbed from the gastrointestinal tract and exhibit oral bioavailability by 54.5% plus or minus 9.1%.
The Valtrex 500mg has human plasma protein binding capacity is 13 to 18%.
Valacyclovir is hastily absorbed and approximately 99% of drug get convinced into an active form like acyclovir & L-valine by sustain first pass metabolism & hepatic metabolism by enzymatic hydrolysis.
Radioactivity gets eliminated via urine is nearly 89%. The mean half life period of valacyclovir is 2.5 to 3.3 hours.
DOSAGE & ADMINISTRATION OF VALTREX
Valtrex tablet should be administered with or without food.
Cold sore (herpes labialis):
The prescribed dose of Valtrexis 2 gram should be taken for two times a day for one day in 12 hours apart.
Genital herpes (initial episode):
The prescribed dose of Valtrexis 1 grams should be taken as twice daily for 10 days.
The prescribed dose is 500mg should be administered orally as twice daily for 3 days.
In ceaseless suppressive treatment, the recommended measurements are 1 gram taken as once every day in patients with typical capacities. In patients with 9 repeats for every year, the recommended dosage is 500mg ought to be regulated as once day by day.
In HIV-1 infected patients:
500mg of Valtrexshould be administered orally as two times a day.
Reduction of transmission:
500mg of Valtrexshould be taken as once daily.
In this condition, the recommended dose of Valtrexis 1gm should be taen as three times a Day for 7 days.
Cold sores (herpes labialis):
The patient’s age of greater or equal to 12 years, the recommended dose of Valtrexis 2 gram should be taken as twice daily for 1 day.
20mg/kg of Valtrexshould be administered orally as three times a day for 5 days. The maximum dose per day is not exceeding 1 gram 3times a day.
The common side effects
Anemia, Increased AST, Neutropenia, Respiratory tract infection, Decreased platelet counts, Nasopharyngitis, Headache, Dizziness, Nausea, Abdominal pain
The major adverse effects of Valtrex 500mg are
Thrombotic thrombocytopenia purpura / hemolytic uremic syndrome, Acute renal failure, Central nervous effects
Central nervous system effects
In pediatric patients with or without renal impairment should be describe with nervous problems like agitation, hallucination, confusion, seizures while on treatment with Valtrex 500mg . In this condition treatment should be stopped.
This circumstances occurs during the treatment using with Valtrex 500mg , this may causes death with chronic HIV-1 disease & bone marrow transplant. In this lethal condition therapy should be immediately stopped & monitor the indication due to this fetal case.
Acute renal failure
Use Valtrex 500mg in geriatric patients very cautiously. Dosage reduction should be necessary for renal impaired patients. Patients who are getting nephrotoxic drugs should be taken care while administration of Valtrex 500mg tablets. Patients have no enough hydration may causes precipitation of acyclovir in renal tubules.
DRUG INTERACTIONS OF VALTREX 500MG
No drug- drug interactions occurs in the valacyclovir therapy.