Valatsiklovir-KR

General characteristics. Structure:

Active ingredient: 1 tablet contains a valatsiklovir of a hydrochloride in terms of валацикловир 500 mg and 1000 mg.

Pharmacological properties:

Pharmacodynamics. Valatsiklovir – antiviral drug, L – the valinovy ether of an acyclovir which is an analog of a purine (guanine) nucleoside. In a human body валацикловир quickly and almost completely turns into an acyclovir and valine by means of a valatsiklovirgidrolaza. The acyclovir is specific inhibitor of viruses of herpes with activity of in vitro against viruses of a herpes simplex of I and II type, the Varicella zoster virus, a cytomegalovirus, Epstein's virus – Burra and a virus of herpes of the person of the VI type. The acyclovir inhibits synthesis of virus DNA right after phosphorylation and transformation into an active form – acyclovir triphosphate. At the first stage of phosphorylation activity of virusospetsifichesky enzyme is necessary. For a virus of a herpes simplex, the Varicella zoster virus and Epstein's virus – Burra is a virus thymidinekinase (shopping mall) which is present only at the cells infected viruses. Partial selectivity of phosphorylation remains at a Cytomegaloviral infection and oposredstvutsya through UL97 fosfotrasnferaza gene product. Activation of an acyclovir specific virus enzyme substantially explains its selectivity. Process of phosphorylation of an acyclovir (transformation from mono - in triphosphate) is carried out by cellular kinases. An acyclovir triphosphate competitively inhibits virus DNA – a polymerase and is incorporated in virus DNA that leads to an obligate (full) rupture of a chain, to the termination of synthesis of DNA and leads to blocking of replication of a virus. Resistance is caused by deficit of shopping mall of a virus which leads to excessive spread of a virus in the owner's organism. Sometimes the reduced sensitivity to an acyclovir is caused by emergence of virus strains with the broken structure virus shopping mall or DNA polymerases. Virulence of these kinds of a virus reminds that as at its wild strain.
Valatsiklovir – KR accelerates the termination of pain at treatment of the surrounding herpes, reduces duration of a pain syndrome, and also the number of patients with zosterassotsiirovanny pain, including with acute and post-herpetic neuralgia.
Prevention of a Cytomegaloviral infection by means of Valatsiklovir – KR reduces risk of acute rejection of a transplant (patients after renal transplantation), the frequency of developing of the opportunistic infections and other infections caused by a herpes virus (a virus of a herpes simplex and the Herpeszoster virus).

Pharmacokinetics. After oral administration валацикловир it is well soaked up, quickly and almost completely turns into an acyclovir and valine. This transformation, obviously, happens by means of enzyme of the valatsiklovirgidrolaza allocated from a liver of the person. Bioavailability of an acyclovir at reception of 1 g of a valatsiklovir makes 54% and does not decrease during meal. Average peak concentration of an acyclovir makes 10 – 37 µmol (2,2 – 8,3 mkg/ml) after use of a single dose of 250 - 2000 mg of a valatsiklovir by patients with normal function of kidneys, and a median of time of achievement of this concentration – 1 – 2 h. Peak concentration of a valatsiklovir in plasma makes only 4% of concentration of an acyclovir and comes, on average, in 30 – 100 min. and in 3 h decreases below the measured quantity. Pharmacokinetic parameters of a valatsiklovir and acyclovir after one-time and repeated introduction are similar. Linkng of a valatsiklovir with proteins of plasma very low – 15%. The acyclovir elimination half-life after one-time and reusable introduction of a valatsiklovir by the patient with normal function of kidneys makes about 3 h Valatsiklovir is brought with urine, mainly in the form of an acyclovir (more than 80% of a dose) and its metabolite a 9-karboksimetoksimetilguanin.

Indications to use:

Treatment of the surrounding herpes; the infections of skin and mucous membranes caused by a herpes simplex virus including primary and recurrent genital herpes; labial herpes (lip fever); preventive treatment (suppression) of a recurrence of infections of skin and the mucous membranes caused by a herpes simplex virus including genital herpes; reduction of transfer of a virus of genital herpes to the healthy partner at Valatsiklovir's use – KR as suppressive therapy in a combination with safe sex; prevention of a Cytomegaloviral infection and disease after organ transplantation.

Route of administration and doses:

Treatment of the surrounding herpes: 1000 mg of Valatsiklovir – KR 3 times a day, within 7 days. Treatment of the infections caused by a herpes simplex virus: 500 mg of Valatsiklovir – KR 2 times a day. For treatment of labial herpes (lip fever) an effective dose of Valatsiklovir – KR is 2000 mg 2 times a day within 1 day. Other dose needs to be accepted approximately in 12 hours after the first dose. At such mode of dosing the term of treatment has to be no more than 1 day as it is proved that longer continuation does not increase clinical performance of treatment. Treatment should be begun at emergence of the first early symptoms of labial herpes. Preventive treatment (suppression) of a recurrence of the infections caused by a herpes simplex virus: appoint sick with normal immunity 500 mg of Valatsiklovir – KR once a day; the patient with an immunodeficiency appoint a dose of 500 mg 2 times pass.
Prevention of a Cytomegaloviral infection and disease: Valatsiklovir – KR is appointed in a dose 2000 mg, 4 times a day, as soon as possible after transplantation. At a renal failure of a dose decrease. Duration of treatment makes usually 90 days, but can be continued for patients with a high risk.

Features of use:

With care appoint to patients with liver diseases.

Side effects:

Headache; dizziness, confusion of consciousness, decrease in mental capacities; nausea; discomfort in a stomach, vomiting, diarrhea, short wind.

Contraindications:

Hypersensitivity to a valatsiklovir, an acyclovir and other drugs, similar on structure. Pregnancy and period of feeding by a breast. Children's age.

Issue conditions:

According to the recipe

Packaging:

The tab. п / about 500 mg No. 5*2 and the tab. п / about 1000 mg No. 5*2