Herpeval

Herpeval is an antiviral medication. Its active component is valacyclovir (the substance is the L-valine ester of acyclovir, which acts as an analogue of the nucleoside of purines (guanine)).

Inside the liver, the active component of the drug with the participation of the element valacyclovir hydrolase is transformed into 2 substances - valine with acyclovir. The therapeutic selectivity of acyclovir can mainly be explained by the fact that it is activated by a specific enzyme of the virus. [1]

Indications Herpeval

It is used in the treatment of such diseases:

• herpes zoster;
• lesions of the mucous membranes and epidermis associated with the herpes simplex virus (this also includes the genital form of herpes of the primary and recurrent type);
• lip fever.

It is used for the preventive therapy of recurrent infections of the epidermis and mucous membranes caused by herpes simplex (also its genital form). It can be prescribed to reduce the likelihood of transmission of genital herpes to a healthy partner during sexual intercourse.

It is prescribed to prevent CMVI and the development of pathologies after organ transplantation.

Release form

The release of the drug is sold in tablets - 10 pieces inside the cell pack; inside the box - 1, 2 or 4 such packs.

Pharmacodynamics

Acyclovir specifically slows down the viral action of herpes in vitro (in relation to common herpes of the 1st and 2nd type, CMV, herpes zoster, EBV and herpesvirus type 5). Its active form is acyclovir 3-phosphate, formed during phosphorylation processes using cell kinases (viral thymidine kinase). This element competitively slows down the DNA polymerase of the virus and is incorporated into its DNA.

Resistance is associated with a lack of viral thymidine kinase, which causes the virus to spread excessively within the body. Sometimes a decrease in sensitivity to acyclovir is associated with the emergence of viral strains in which the integrity of the DNA polymerase or TC virus structure is disrupted. [2]

In persons with healthy immunity, the virus with a weakened sensitivity to acyclovir is observed singly and sometimes develops only in people with severe immune disorders. [3]

Pharmacokinetics

Valacyclovir has good absorption, it is almost fully transformed at high speed into valine with acyclovir. The bioavailability index of acyclovir in the case of taking 1 g of valacyclovir is 54% (without reference to food intake). The Cmax values of acyclovir are equal to 10-37 μmol when a single dose of 0.25-2 g is administered (after 1-2 hours from the moment of taking the drug). The plasma level of valacyclovir is 4% of the values of acyclovir and is recorded after 30-100 minutes (on average); after 3 hours, it decreases to a mark below the defined boundary.

Protein synthesis of valacyclovir is extremely low - 15%.

The half-life of acyclovir is approximately 3 hours; in people with renal insufficiency in the terminal phase - about 14 hours. Valacyclovir is excreted in the urine, mainly in the form of acyclovir (over 80% of the dosage), as well as its metabolic element 9-carboxymethoxymethylguanine.

Dosing and administration

For herpes zoster: apply 2 tablets (1 g) of drugs, 3 times a day, during the 1st week.

Therapy for infections associated with the herpes simplex virus.

Persons with healthy immunity - 1 tablet (0.5 g), 2 times a day.

In case of relapses, therapy lasts 3-5 days. In the case of primary treatment, which may be more difficult, the course is 10 days. It is necessary to start therapy with relapses of the herpes simplex virus as early as possible - it is considered optimal to take the medication during the prodromal stage or immediately after the first signs appear. The drug is able to prevent the appearance of lesions in case of relapse, if therapy is started immediately after the development of the first manifestations of the disease.

Alternatively, in the treatment of labial fever, a dosage of 4 tablets (2 g) is prescribed, 2 times a day. The second serving should be consumed approximately 12 hours (at least 6 hours later) after the first dose. At the indicated dosages, the duration of therapy should be a maximum of 1 day, since it was found that longer use does not increase the medicinal efficacy. Treatment should be started immediately after the onset of early signs of lip fever (itching, tingling, or burning on the lips).

Suppression of recurrent infections associated with herpes simplex virus:

• persons with healthy immunity are prescribed 1 tablet of drugs (0.5 g), 1 time per day;
• with immunodeficiency, it is required to use 1 tablet (0.5 g) 2 times a day.

Reducing the likelihood of transmission of genital herpes.

With healthy immunity in persons with nine or fewer exacerbations of the disease per year, Gerpeval is prescribed at a dosage of 0.5 g 1 time per day.

Prevention of the development of CMVI and pathologies after organ transplantation.

The medicine is used in a dosage of 4 tablets (2 g), 4 times a day, as quickly as possible after transplantation. In case of failure of the kidneys, the portions are reduced. Therapy usually lasts 3 months, but may be prolonged in people at increased risk.

• Application for children

It is prescribed for children from 12 years old to prevent the development of CMVI or pathologies after transplantation.

Use Herpeval during pregnancy

It is allowed to use Herpeval during pregnancy only in cases where the possible benefit from it is more likely than the risks of complications for the fetus.

With hepatitis B, the medication is prescribed with caution, only when absolutely necessary. In this case, valacyclovir can be used for therapy in newborns.

Contraindications

It is contraindicated to use in case of severe intolerance to acyclovir and other elements of the drug.

Side effects Herpeval

The main side effects:

• disorders in the field of the National Assembly and psyche: dizziness, hallucinations, cephalalgia, agitation, confusion, weakening of intellectual abilities and ataxia, and besides this, convulsions, tremors, dysarthria, encephalopathy, psychotic signs and coma;
• problems with the digestive tract: diarrhea, nausea, abdominal discomfort and vomiting;
• disorders associated with the hepatobiliary system: a temporary increase in liver function tests (sometimes described as hepatitis);
• signs in the area of the lymph and blood system: thrombocyto- or leukopenia (the latter is mainly observed in persons with immunodeficiency);
• immune lesions: anaphylaxis occurs occasionally;
• disorders of the respiratory system and sternum organs: dyspnea;
• symptoms affecting the subcutaneous layer and epidermis: a rash that includes signs of photosensitivity, Quincke's edema, urticaria and itching;
• disorders of the kidneys and urinary system: acute renal failure, renal dysfunction, pain in the lumbar region and hematuria (often associated with other renal dysfunctions). Renal pain may be associated with kidney failure;
• others: there is information about insufficient renal function, hemolytic anemia of microangiopathic type and thrombocytopenia (sometimes combined) in people with severe immunodeficiency, especially in people with HIV at a later stage, who have been using valacyclovir in large doses for a long time (8 g per day)... Similar symptoms were observed in people with similar pathologies who did not use valacyclovir.

Overdose

Signs of poisoning: vomiting, acute renal failure, nausea, neurological manifestations, including hallucinations, confusion, loss of consciousness, agitation and coma.

Symptomatic measures and hemodialysis are carried out.

Interactions with other drugs

Valacyclovir is excreted in the urine with active tubular secretion, which is why other drugs competing for this mode of excretion can increase the plasma levels of one or both drugs and their metabolic elements.

Administration of mycophenolate in combination with mycophenolate mofetil (an immunosuppressive agent used in organ transplantation) increases the values of acyclovir and the inactive metabolic component of mycophenolate mycophenolate mofetil within plasma.

It is necessary to carefully combine large dosages of Gerpeval (4+ g) with other drugs that alter renal function (for example, tacrolimus or cyclosporine).

Storage conditions

Herpeval must be kept out of the reach of small children. Temperature indicators are no more than 30 ° C.

Shelf life

Herpeval can be used for 24 months from the date of manufacture of the therapeutic substance.

Analogs

The analogues of the medication are Vairova, Vatsirex, Valtsikon with Valavir, Valmik and Valmax with Valatsitek. In addition, Valogard, Valtrovir with Herpacicvir, Valzik and Virdel are on the list.