Welcome to your new blog community that has just been launched!
Valaciclovir Systematic (IUPAC) name 2-ethyl CAS number 124832-26-4 ATC code J05AB11 PubChem 60773 DrugBank APRD00697 ChemSpider 54770 Chemical data Formula C13H20N6O4 Mol. mass 324. 336 g/mol SMILES eMolecules & PubChem Pharmacokinetic data Bioavailability 55% Protein binding 13–18% Metabolism Hepatic (to aciclovir) Half life <30 minutes (valaciclovir); 2. 5-3. 6 hours (aciclovir) Excretion Renal 40–50% (aciclovir), faecal 47% (aciclovir) Therapeutic considerations Pregnancy cat. B3 (Au), B (U. S. ) Legal status S4 (Au), POM (UK), (U. S. ) Routes Oral Valaciclovir (INN) or valacyclovir (USAN) is antiviral used in the management of herpes simplex and herpes zoster (shingles). It is a prodrug, being converted in vivo to aciclovir. It is marketed by GlaxoSmithKline under the trade name Valtrex or Zelitrex. Contents 1 Pharmacology 1. 1 Mechanism of action 1. 2 Microbiology 1. 3 Ingredients 2 Clinical use 2. 1 Indications 2. 2 Adverse effects 3 References External links // Pharmacology Mechanism of Valaciclovir is a prodrug, an esterified version of aciclovir that has greater oral bioavailability (about 55%) than aciclovir (10-20%). It is converted esterases to the active drug aciclovir, well as the amino acid valine, via hepatic first-pass metabolism. Acyclovir is selectively converted into monophosphate form by viral thymidine kinase, which is far more (3000 times) in than cellular kinase. Subsequently, monophosphate form is further phosphorylated into the triphosphate form, aciclo-GTP, by cellular kinases. Aciclo-GTP is a very inhibitor of viral DNA it has approximately 100 times higher affinity to viral than cellular polymerase. Its monophosphate form also incorporates into the viral DNA, resulting in termination. It also been shown that the viral enzymes cannot remove aciclo-GMP from the chain, which results in inhibition of further of DNA Aciclo-GTP is fairly rapidly metabolised within the cell, possibly by cellular phosphatases. Microbiology Aciclovir, the active metabolite of valaciclovir, is active against most species in the herpesvirus family. In descending of Herpes simplex virus type I (HSV-1) Herpes simplex virus type II (HSV-2) zoster virus (VZV) Epstein-Barr virus (EBV) Cytomegalovirus (CMV) Activity is predominantly against HSV, and to a lesser VZV. is only of limited efficacy EBV and CMV, has recently been shown to lower or the presence of the Epstein-Barr virus in subjects afflicted with acute mononucleosis, leading to a significant decrease in the severity of symptoms. It is inactive against latent viruses in nerve ganglia. To date, resistance to valaciclovir has not been clinically significant. Mechanisms of resistance HSV include deficient viral thymidine kinase; and mutations to viral thymidine kinase and/or DNA polymerase, altering substrate sensitivity. Ingredients Valtrex is offered in 500 mg and 1gram tablets, active ingredient being valacyclovir hydrochloride, with the inactive ingredients carnauba wax, colloidal silicon crospovidone, FD&C Blue No. 2 Lake, hypromellose, magnesium microcrystalline cellulose, polyethylene glycol, polysorbate 80, povidone, titanium dioxide. Clinical Indications Valtrex brand valaciclovir 500mg tablets Valaciclovir is indicated for the treatment of HSV and VZV infections, including: Genital herpes (treatment and prophylaxis) Reduction of HSV transmission from people with infection to uninfected individuals Herpes zoster (shingles) Prevention of CMV following organ transplantation It has shown promise as a treatment for infectious mononucleosis and is preventatively administered in suspected cases of Herpes B Virus exposure. Adverse effects Common adverse drug reactions (≥1% of patients) associated valaciclovir therapy the same as for aciclovir, its active metabolite, and include: nausea, vomiting, diarrhea, anal leakage and/or headache. Infrequent adverse effects (0. 1–1% of patients) include: agitation, vertigo, confusion, dizziness, edema, sore throat, constipation, abdominal pain, rash, and/or renal impairment. Rare adverse effects (<0. 1% of patients) coma, seizures, neutropenia, leukopenia, tremor, enc
