Country: Malaysia
Bahasa: Inggeris
Sumber: NPRA (National Pharmaceutical Regulatory Agency, Bahagian Regulatori Farmasi Negara)
VALACICLOVIR HYDROCHLORIDE
CAMBER LABORATORIES SDN. BHD.
VALACICLOVIR HYDROCHLORIDE
100Tablet Tablets; 100Tablet Tablets; 100Tablet Tablets
Hetero Labs Limited
VALOVIR Valaciclovir Tablet 500 mg DESCRIPTION AND COMPOSITION: White to off-white, film coated, caplet shaped tablets, debossed with 'V' on one side and '500' on other side. Each film coated tablet contains: Valaciclovir Hydor- chloride 556mg equivalent to Valaciclovir 500mg PHARMACODYNAMIC PROPERTIES: Valaclovir an antiviral, is the L-valine ester of acyclovir. Aciclovir is a purine (guanine) nucleoside analogue. MODE OF ACTION: Valaciclovir is rapidly and almost completely converted in man to acyclovir and valine, probably by the enzyme referred to as valaciclovir hydrolase. Aciclovir is a specific inhibitor of the herpes viruses with in vitro activity against herpes simplex viruses (HSV) type 1 and type 2, varicella zoster virus (VZV), cytomegalvorus (CMV), Epstein- Bair Virus (EBV) and human herpes virus 6 (HHV-6). Aciclovir inhibits herpes virus DNA synthesis once it has been phosphorylated to the active triphosphate form. The first stage of phosphorylation requires the activity of a virus-specific enzyme. In the case of HSV, VZV and EBV this enzyme is the viral thymidine kinase (TK), which is only present in virus infected cells. Selectivity is maintained in CMV with phosphorylation, at least in part, being mediated through the phosphotransferase gene product of UL97. This requirement for activation of acyclovir by a virus specific enzyme largely explains its selectivity. The phosphorylation process is completed conversion from mono to triphosphate by cellular kinases. Aciclovir triphosphate competitively inhibits the virus DNA polymerase and incorporation of this nucleoside analogue results in obligate chain termination, halting virus DNA synthesis and this blocking virus replication. Extensive monitoring of clinical HSV and VZV isolates from patients receiving acyclovir therapy or prophylaxis has revealed that virus with reduced sensitivity to acyclovir is extremely rare in the immunocomptetent and is only found infrequently in severely immuno compromised individuals e.g. organ or bone marrow transplant Baca dokumen lengkap