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Valtrex online
Pharmacological action
Antiviral drugs. Is a specific inhibitor of DNA polymerase of herpes viruses. Blocks of viral DNA synthesis and replication of viruses.
In the body, valacyclovir becomes acyclovir and valine. As a result of phosphorylation of acyclovir into active acyclovir triphosphate, which is competitive inhibition of viral DNA polymerase. The first stage of phosphorylation occurs under the influence of virus-specific enzyme. For buy valtrex online money grahm Herpes simplex, Varicella zoster and Epstein-Barr virus by this enzyme is a viral thymidine kinase, which is found only in cells infected with the virus. For cytomegalovirus selectivity of the drug due to the fact that phosphorylation, at least in part, mediated by the product of the gene fosfotransferazy UL97. The need for virus-specific enzyme activation acyclovir largely explains its selectivity.
Valacyclovir in vitro is active against Herpes simplex virus types 1 and 2, Varicella zoster and Epstein-Barr virus, cytomegalovirus and human herpes virus type 6.
Extensive study of clinical strains isolated from patients showed that patients with normal immunity viruses with reduced sensitivity to aciclovir are found only rarely. Several more, or relatively rare, these viruses are found in patients with marked immune deficiency, eg in recipients of internal organs or bone marrow in patients receiving chemotherapy for malignant neoplasms, and people living with HIV. Decreased sensitivity of viruses to aciclovir phenotype is caused by deficiency of thymidine kinase in cells infected with the virus. Rarely cause reduced sensitivity to acyclovir were hidden changes in viral thymidine kinase or DNA polymerase.
Pharmacokinetics
The pharmacokinetics of valaciclovir and acyclovir is similar for single and repeated use.
The absorption, distribution and metabolism
After oral administration valaciclovir is well absorbed from the gastrointestinal tract, is rapidly and almost completely converted to acyclovir and L-valine, possibly under the action of the enzyme valatsiklovirgidrolazy.
Bioavailability of acyclovir when receiving 1 g of valaciclovir is 54% and not reduced under the influence of food.
Acyclovir Cmax after single dose 0.5-1 g Valacyclovir is an average of 15-25 micromol / ml and is reached after an average of 1.5 h after administration. Cmax valaciclovir in plasma is only 4% of the acyclovir and achieved an average of 45-60 minutes after dosing, after 3 h valacyclovir in plasma is not defined.
Valacyclovir binding to plasma proteins is very low – 15%.
Withdrawal
T1 / 2 acyclovir after single and repeated application valaciclovir is approximately 3 hours Less than 1% of the administered dose generic valtrex is determined in the urine. Valacyclovir is excreted in the urine, mainly in the form of acyclovir and its metabolite 9-karboksimetoksimetilguanina.
Indications
- Treatment of herpes zoster;
- Treatment of diseases of the skin and mucous membranes caused by Herpes simplex virus types 1 and 2 (including the first identified and recurrent genital herpes) can you drink alcohol while taking valtrex;
- Prevention of recurrence of disease of the skin and mucous membranes caused by Herpes simplex virus types 1 and 2 (including genital herpes);
- Prevention of cytomegalovirus infection and disease developing after organ transplantation. Prophylaxis with valtrex generic reduces transplant rejection reaction, the development of infections caused by opportunistic microorganisms, and other viral infections (including herpes zoster).
Dosage regimen
For the treatment of herpes zoster appoint 1 g 3 times / day for 7 days.
For the treatment of diseases caused by Herpes simplex, Valtrex prescribed 500 mg 2 times / day.
In recurrent disease, caused by the virus Herpes simplex, treatment is best to begin in the prodromal period or immediately after the first symptoms. Duration of treatment – 3-5 days. In the first episode, which can proceed more difficult, the duration of treatment can be increased up to 10 days, appoint a drug should be as soon as possible.
To prevent a recurrence of diseases caused by the virus Herpes simplex, adults with normal immune indicators prescribed 500 mg 1 time per day. With very frequent exacerbations (more than 10 times per year) may be more effective assignment of 250 mg 2 times / day. Adults with immunodeficiency prescribed 500 mg 2 times / day.
For the prevention of cytomegalovirus infection in adults and adolescents over 12 years, the dose is 2 g 4 times / day. The drug is prescribed as soon as possible after transplantation. The dose can be changed in accordance with creatinine clearance. Course duration is usually 90 days, but can be increased in patients with high risk of infection.
Patients with impaired renal function dosing regimen set according to creatinine clearance and evidence.
Indications Creatinine Clearance Dosage valtrex coupon
treatment of herpes zoster 15-30 ml / min 1 g 2 times / day
less than 15 ml / min 1 g 1 time / day
treatment of infections caused by Herpes simplex at least 15 ml / min 500 mg 1 time / day
prevention of infections caused by Herpes simpleh
less than 15 ml / min 250 mg 1 time / day (normal rates of immunity)
500 mg 1 time / day (with immunodeficiency)
For the prevention of cytomegalovirus infection following recommended doses.
Creatinine clearance (ml / min) Dose of Valtrex
75 or more than 2 g 4 times / day
50-less than 75 1.5 g 4 times / day
25-less than 50 1.5 g 3 times / day
10-less than 25 1.5 g 1 time / day
In renal failure patients on hemodialysis, how fast does valtrex work should be administered at the dose recommended for patients with CC than 15 ml / min. The drug should be used after hemodialysis.
Patients with impaired hepatic function mild to moderate degree of correction required dosage. In the study of pharmacokinetics in patients with severe cirrhosis and a violation of synthetic liver function is not obtained evidence of the need to correct dosing regime, but clinical experience with the drug Valtrex in this category of patients is organic.
Side effects
From the digestive system: nausea, vomiting, diarrhea, discomfort, rarely – transient increase in indexes of liver samples.
From CNS: Rarely – headache is very rare – reversible neurological disorders, such as dizziness, confusion, hallucinations (usually in patients with impaired renal function or other predisposing factors).
Allergic reactions: seldom – rash, urticaria, pruritus, angioedema, anaphylaxis.
Other: rarely – thrombocytopenia, dyspnea, impaired renal function.
In patients with marked immunodeficiency, receiving high-dose valacyclovir (8 g / day) for a long time, described the cases of renal failure, microangiopathic hemolytic anemia and thrombocytopenia (sometimes in combination with each other). It should be noted that to date the relationship between the development described adverse reactions and the application buy valtrex not completely installed.
Contraindications
- Hypersensitivity to valacyclovir, acyclovir.
Pregnancy and lactation
There are limited data on the use of Valtrex during pregnancy. Valtrex is used only in cases where the potential benefits to the mother justifies potential risk to the fetus. Specially recorded all cases of Valtrex and Zovirax (acyclovir all dosage forms) in pregnancy: there were reports of 111 and 1,246 cases respectively (one in 29 and 756 cases respectively, the drug was prescribed in I trimester). With regard to acyclovir did not identify the specificity of congenital defects or increase the frequency of birth defects in babies born to mothers who took Zovirax during pregnancy, compared with the general population. Given the small number of buy famvir, zovirax and valtrex patients the final conclusions on the safety of valaciclovir in pregnancy can not be made.
Main metabolite of valaciclovir is acyclovir, which is excreted in breast milk. Concentrations of acyclovir in breast milk is 0.6-4.1 of its respective plasma concentrations.
After receiving Zovirax oral dose of 200 mg 5 times a day Sssmax average of 3.1 mmol / ml (0.7 mg / ml). At such concentrations in breast milk, children who are breastfed may receive acyclovir at a dose of up to 0.3 mg / kg body weight / day. Given this, caution should be exercised in the appointment of Zovirax in the period of lactation (breastfeeding). The half-life acyclovir in breast milk of 2.8 h, which is comparable to the half-life of blood plasma. It should be borne in mind that at doses of 30 mg / kg / day acyclovir prescribed to treat neonatal infections caused by herpes simplex virus.
Recommend caution in the appointment of buy valtrex on line during lactation.
Cautions
Elderly patients during treatment Valtrex need to increase fluid intake.
Use in Pediatrics
Experience of clinical application of the drug in children is absent.
Overdose
At present, cases of overdose Valtrex were reported.
Unintentional single i / v infusion of acyclovir at a dose of 80 mg / kg, corresponding to about 15 g of cost of valtrex, not accompanied by side effects.
Treatment: Acyclovir is derived by hemodialysis.
Drug Interactions
Unknown clinically significant drug interactions Valtrex with other drugs.
Conditions and terms of storage
The drug should be stored at temperatures not above 30 ° C. Shelf life – 3 years.
Conditions of supply of pharmacies
The drug is released with a prescription.
