Zovirax pills 200mg №25

Active ingredient and dosage form

Pills blue, flat, in the form of a shield (of irregular polygonal shape), with the inscription "ZOVIRAX" extruded on one side and a triangle on the other; slight blotches may be visible on the pill surface.
1 pill contains Acyclovir 200 mg;
Excipients: lactose monohydrate, sodium starch glycolate, povidone K30, Magnesium stearate, indigo carmine.
25 pcs. packaged.

Mechanism of action

Zovirax is an antiviral drug, a synthetic analog of the purine nucleoside, which has the ability to inhibit in vitro and in vivo replication of Herpes simplex type 1 and 2 viruses, Varicella zoster virus, Epstein-Barr virus (EBV) and cytomegalovirus (CMV). In cell culture, acyclovir has the most pronounced antiviral activity against Herpes simplex type 1, then in order of decreasing activity follow: Herpes simplex type 2, Varicella zoster, EBV and CMV.
The effect of acyclovir on viruses is highly selective. Acyclovir is not a substrate for the enzyme thymidine kinase of uninfected cells; therefore, it is of low toxicity to mammalian cells. Thymidine kinase of cells infected with Herpes simplex type 1 and 2 viruses, Varicella zoster, EBV and CMV, converts acyclovir into acyclovir monophosphate, a nucleoside analogue, which is then sequentially converted to diphosphate and triphosphate under the action of cellular enzymes. The inclusion of acyclovir triphosphate in the chain of viral DNA and the subsequent chain termination block further replication of viral DNA.
In patients with severe immunodeficiency, prolonged or repeated courses of therapy with acyclovir can lead to the formation of resistant strains, and therefore further treatment with acyclovir may be ineffective. Most of the isolated strains with reduced sensitivity to acyclovir showed a relatively low content of viral thymidine kinase, a violation of the structure of viral thymidine kinase or DNA polymerase. The effect of acyclovir on strains of the Herpes simplex virus in vitro can also lead to the formation of less sensitive strains. The correlation between the sensitivity of Herpes simplex virus strains to acyclovir in vitro and the clinical efficacy of the drug has not been established.
It was shown that intravenous injection of Zovirax in high doses reduces the frequency of occurrence and retards the development of cytomegalovirus infection. If, after such infusion therapy, treatment with acyclovir is administered for oral administration in high doses for 6 months, then mortality and the incidence of viremia will decrease.

Indications and usage

- treatment of infections caused by the Herpes simplex type 1 and 2 virus;
- prevention of infections caused by the virus Herpes simplex type 1 and 2, in patients with immunodeficiency;
- treatment of infections caused by the virus Varicella zoster (chicken pox and herpes zoster);
- treatment of infections caused by the Herpes simplex virus type 1 and 2 in newborns;
- prevention of cytomegalovirus infection in bone marrow transplant recipients

Contraindications

- Hypersensitivity to acyclovir or valacyclovir.
WITH caution should be used during dehydration, renal failure, neurological disorders, as well as during the development of reactions to cytotoxic drugs when they are in / in the introduction (and when indicating such reactions in history).

Dosage and administration

For adults for the treatment of Herpes simplex type 1 and 2 infectionsThe recommended dose of Zovirax is 200 mg 5 times / day every 4 hours (except during the period of night sleep). Usually, the course of treatment is 5 days, but may be prolonged with severe primary infections.
At severe immunodeficiency (for example, after bone marrow transplantation) or intestinal absorption disorder Zovirax dose for oral administration can be increased to 400 mg 5 times / day. Treatment should begin as soon as possible after the onset of infection; in case of relapses, it is recommended to prescribe the drug in the prodromal period or when the first elements of the rash appear.
For prevention of recurrence of infections caused by the virus Herpes simplex type 1 and 2at patients with normal immune status The recommended dose of Zovirax is 200 mg 4 times / day (every 6 hours). A more convenient treatment regimen is suitable for many patients: 400 mg 2 times / day (every 12 hours). In some cases, lower doses of Zovirax are effective: 200 mg 3 times / day (every 8 hours) or 2 times / day (every 12 hours). Zovirax treatment should be periodically interrupted for 6-12 months to identify possible changes in the course of the disease.
For preventing the occurrence of infections caused by the herpes simplex type 1 and 2 virusat immunocompromised patients The recommended dose of Zovirax is 200 mg 4 times / day (every 6 hours). At severe immunodeficiency (for example, after bone marrow transplantation) or intestinal absorption disorder Zovirax dose for oral administration can be increased to 400 mg 5 times / day. The duration of the prophylactic course of therapy is determined by the duration of the risk of infection.
For treating varicella and herpes zoster The recommended dose of Zovirax is 800 mg 5 times / day, the drug is taken every 4 hours, except during the night's sleep. The course of treatment is 7 days.
The drug should be prescribed as soon as possible after the start of infection, because in this case, the treatment is more effective.
For treatment of patients with severe immunodeficiency The recommended dose of Zovirax is 800 mg 4 times / day (every 6 hours).
Patients undergoing bone marrow transplantation, before Zovirax is administered orally, it is usually recommended to conduct a course of intravenous therapy with acyclovir for 1 month. In clinical trials, the maximum duration of treatment for bone marrow transplant recipients was 6 months (from the 1st to the 7th month after transplantation). In patients with a comprehensive clinical picture of HIV infection, Zovirax was treated for 12 months, but there is reason to believe that longer-term therapy may be effective in such patients.
Treatment and prevention of infections caused by Herpes simplex virusesat children with immunodeficiency ages 2 and older - the same doses as for adults; at under 2 years old - half the dose for adults.
For chickenpox treatment children over 6 years old the drug is prescribed in a single dose of 800 mg; from 2 to 6 years - 400 mg; under 2 years old - 200 mg. The multiplicity of reception 4 times / day. More precisely, a single dose can be determined at the rate of 20 mg / kg body weight (but not more than 800 mg). The course of treatment is 5 days.
Data on the use of Zovirax for prevention of recurrent infections caused by Herpes simplex virusesand during treatment herpes zoster at children with normal levels of immunity are missing.
According to very limited treatment information. children over 2 years old with severe immunodeficiency You can apply the same dose of Zovirax as for the treatment of adults.
When appointing Zovirax elderly patients Consideration should be given to the possibility of a decrease in clearance of acyclovir in parallel with a decrease in creatinine clearance. If there are signs of renal failure, it is necessary to resolve the issue of reducing the dose of Zovirax. Elderly patients should receive a sufficient amount of fluid while taking Zovirax orally in high doses.
In patients with renal failure taking oral acyclovir in recommended doses for the purpose of treatment and prevention of infections caused by Herpes simplex viruses, does not lead to the accumulation of the drug to concentrations exceeding the established safe levels. However, in patients with QC less than 10 ml / min Zovirax dose is recommended to reduce to 200 mg 2 times / day (every 12 hours). For treating varicella, herpes zosteras well as for the treatment of patients with severe immunodeficiency at QC less than 10 ml / min The recommended dose of Zovirax is 800 mg 2 times / day every 12 hours; at QC 10-25 ml / min 800 mg 3 times / day every 8 h.
Zovirax tablets can be taken with meals, since the intake of food does not significantly affect its absorption. Tablets should be taken with a full glass of water.

From the digestive system: nausea, vomiting, reversible increases in bilirubin levels and liver enzymes; very rarely - hepatitis, jaundice.
From the hemopoietic system: anemia, leukopenia and thrombocytopenia.
From the urinary system: rarely - an increase in the level of urea and creatinine in the blood, which is associated with the value of C_max and the patient’s water balance. To avoid such phenomena, the drug should be administered in the form of a slow infusion over 1 hour and to maintain the water balance of the patients. The signs of renal failure that occurred during Zovirax therapy are usually quickly stopped when patients rehydrate and / or reduce the dose of the drug or cancel it. Progression to acute renal failure occurs in exceptional cases.
From the side of the central nervous system: reversible neurological disorders, such as confusion, hallucinations, agitation, tremor, drowsiness, psychosis, convulsions, and coma (usually in predisposed patients).
Allergic reactions: rash, photosensitivity, urticaria, pruritus, fever; rarely - shortness of breath, angioedema, anaphylaxis.
Local reactions: severe inflammatory reactions leading to necrosis were observed when Zovirax solution got under the skin.

Appointment of Zovirax during pregnancy and lactation (breastfeeding) requires caution and is possible only after assessing the intended benefits to the mother and the potential risk to the fetus and child.
There was no increase in the number of birth defects in children whose mothers received Zovirax during pregnancy compared with the general population.
When using Zovirax in the form of a lyophilisate during lactation (breastfeeding), it should be borne in mind that after taking Zovirax orally at a dose of 200 mg 5 times / day, acyclovir was determined in breast milk at concentrations of 0.6-4.1% of plasma concentrations. At such concentrations in breast milk, infants who are breastfed can receive acyclovir at a dose of up to 0.3 mg / kg / day.

In patients with herpetic encephalitis who receive Zovirax in high doses, it is necessary to control the function of the kidneys (especially during dehydration or in the event of an initial impairment of renal function).
With caution and under the control of kidney function, Zovirax should be used simultaneously with drugs that affect kidney function (for example, cyclosporine, tacrolimus).
Patients taking Zovirax in high doses should receive a sufficient amount of liquid.
During therapy, ophthalmic ointment should not wear contact lenses.

Symptoms: increased serum creatinine, blood urea nitrogen, renal failure. Neurological symptoms include confusion, hallucinations, agitation, convulsions, and coma.
Treatment: conduct symptomatic therapy. Hemodialysis is indicated.

There were no clinically significant interactions of Zovirax with other drugs.
Calcium channel blockers and cimetidine increase the AUC of acyclovir and reduce its renal clearance (correction of Zyvirax dosing regimen is not required).
With simultaneous use of Zovirax with drugs excreted by active tubular secretion, it is possible to increase the concentration of the active substances or their metabolites in the plasma (caution is necessary when prescribing such combinations).
The combined use of acyclovir and mycophenolate mophenyl, an immunosuppressant used in organ transplantation, leads to an increase in the AUC of acyclovir and the inactive metabolite of mycophenolate mophenyl.

The drug should be stored out of reach of children at a temperature not exceeding 30 ° C.

- 5 years.