Valaciclovir is a modern analogue of the antiviral drug Acyclovir. It includes a derivative of the active substance, which in the body turns into an active compound. Thanks to the improved mechanism of action, the bioavailability of the drug increases, the likelihood of adverse reactions decreases.
Material Content:
The composition of the drug
A medical product has a single pharmacological form - tablets. The appearance of the products, the accepted packaging for which each manufacturer is individual, is packaged in blisters, as well as plastic or glass bottles. They can be white or dark blue, round, as well as oblong oval in shape, with risks, chamfers, logo printing and engraving.
Under different brands, drugs are available in dosages of 500 and 1000 mg. The therapeutic effect is provided by valaciclovir, which is part of the composition. This is an acyclovir ester, which turns into an active substance in the body under the influence of liver enzymes.
The drug is part of the drug in the form of hydrochloride in the amount of 556 and 1112.4 mg. The tablet gets the rest of the mass due to natural starch, dietary fiber, magnesium salts and silicon.
The surface of the pill is covered with a thin smooth shell, consisting mainly of polyethylene glycol and polyvinyl alcohol. It may also include a dye in white or blue. The shelf life of the medicine is limited to three years.
Pharmacological properties and indications for use
Immediately after absorption by the action of hepatic enzymes, valaciclovir breaks down into acyclovir and an amino acid. Acyclovir has selective activity. It works only inside a cell infected with viruses: herpes (herpes simplex) 1, 2 and sixth type, varicella-zoster (herpes zoster), cytomegalovirus, Epstein-Barr. The active substance has no effect on healthy cells.
The selectivity of a chemical compound is explained by the presence of a specific viral protein, thymidine kinase, in the infected cell. This enzyme starts the acyclovir conversion reaction, turns into active triphosphate, which, being very similar in structure to the nucleoside of viral DNA, integrates into the chain, breaks it and stops the process of copying the virus.
As a result of a decrease in the activity of the pathogen, the symptoms of the disease die out. Pain, itching and inflammation in the affected areas become less pronounced.
The drug helps to cope with the symptoms of primary infection, reduces the recurrence periods of relapses, prolongs the period of remission.
It has been used since twelve years in the treatment of:
- cold sores on the lips;
- skin rashes caused by the herpes simplex virus;
- mucosal lesions with a simple and genital virus;
- Shingles caused by varicella zoster.
It is prescribed to prevent relapse. In combination with barrier contraception, a medicine can reduce the likelihood of a partner becoming infected. It is also used as a preventive measure to prevent infection with cytomegalovirus infection during a kidney transplant.
The drug is not able to completely get rid of the virus. However, it significantly inhibits its activity.
Instructions for use and dosage of Valaciclovir
Valacyclovir tablets can be taken anytime before and after meals. Food does not interfere with the absorption of the drug, nor does it prevent the occurrence of side effects.
Treatment should begin as early as possible with the appearance of the first signals of infection. Even when it comes to relapse, timely treatment can prevent the growth of affected areas of the skin and mucous membranes.
The dose for the treatment of diseases provoked by simple and genital herpes is half a gram. Pills are taken twice a day, preferably after an equal period of time.
With recurrent herpes, the duration of therapy is from three to five days. Primary infection is characterized by a brighter clinical picture and therefore requires an increase in the duration of the course to 10 days.
An alternative regimen has been developed for the treatment of cold sores on the lips. Therapy is carried out in two divided doses and lasts only a day. With the first hints of the disease (itching, burning), you need to drink 2000 mg of the drug, and after 12 hours, repeat the same dose.
Relapse prevention is carried out by long-term medication for four to twelve months. Patients with normal immune status are prescribed one tablet (Valacyclovir 500) per day. With often recurring manifestations (more than ten episodes per year), the daily dose can be divided into two doses, which will ensure the most frequent intake of the substance in the blood.
With established immunodeficiency, the daily dose must be increased to 1000 mg. The total amount of the drug is recommended to be divided into two doses.
Evaluation of the effectiveness of preventive treatment is carried out at least six months later.
Valacyclovir helps prevent the development of cytomegalovirus infection in patients undergoing kidney transplant surgery. Preventive measures are prescribed by the drug as soon as possible at the end of the procedure. An effective dose is the amount of 2000 mg. The drug is taken four times a day for three months.
Symptoms of herpes zoster and ophthalmic herpes are stopped with a dose of one gram. The medicine is drunk for seven days three times a day.
Long-term treatment requires constant monitoring of the condition of the kidneys. It is especially often necessary to carry out monitoring after an organ transplant, since its work during the rehabilitation period will be unevenly tuned.
Kidney capacity is considered when selecting a dose for the elderly. In old age, it is not only necessary to reduce the dose of the drug, but also to monitor the flow of a normal amount of fluid into the body, avoiding disturbance of water-electrolyte balance.
During pregnancy and lactation
It cannot be stated unequivocally that it is safe to take medicine during pregnancy. To draw such conclusions, a large-scale study is needed. At the moment, there are only records of observations of two groups of pregnant women, numbering 700 and 1000 people.
Their results did not reveal an increase in the number of pathologies of fetal development and the course of pregnancy while taking medication. However, due to the small number of test groups, such information cannot be relied on. Therefore, Valaciclovir is prescribed to pregnant women only in anticipation of a significant excess of the benefits over the risk.
At the same time, animal experiments indicate that acyclovir preparations in normal amounts do not affect the ability to conceive, however, high doses administered intravenously can lead to hormonal disruptions.
Acyclovir, as an active metabolite of valaciclovir, is excreted in the milk of a nursing mother, and its maximum concentration in this fluid is 1.4 times higher than that found in blood plasma.
If the mother is being treated, then the child accordingly receives a therapeutic dose of the drug from her. Acyclovir as an intravenous injection is used in infants in the treatment of herpes simplex. Such a remedy during breastfeeding is prescribed only if there are strict indications in the mother and fetus.
Alcohol compatibility
Instructions for use of the drug does not contain information about the compatibility of the drug with alcohol-containing drinks. However, it should be assumed that taking them will enhance the toxic effect of the substance on the kidneys.
Drug interaction
The drug does not react with other drugs, however, it can compete with drugs that, like acyclovir, are excreted from the body by renal filtration. Simultaneous administration with such medications helps to increase the concentration of acyclovir or a competing substance in the blood.
For the same reason, you need to carefully monitor the health of the patient while prescribing Valaciclovir and nephrotoxic drugs. Assessment of the patient's condition is carried out by monitoring renal function, including a study of the conductivity of these organs.
Contraindications, side effects and overdose
Despite the fact that life-saving acyclovir preparations are prescribed from infancy, Valacyclovir tablets are not recommended for children under twelve years of age. If the patient has a sensitivity to any components of the substance, such a patient should also refrain from such treatment.
The following adverse reactions were identified in the totality of complaints about the drug:
- headache, dizziness, abdominal discomfort, nausea, diarrhea, skin itching, allergic manifestations, photosensitivity development;
- trembling of the extremities, convulsions, hallucinations, confusion, shortness of breath, asphyxia, leukopenia, thrombocytopenia;
- hepatitis, renal colic, renal failure, angioedema, coma.
The most serious consequences are more often manifested in people with immunodeficiency, as well as in patients who are forced to consume high doses of the drug for a long time (8 g per day).
Most severe changes are reversible. However, the recommended doses exceed dangerous. Exceeding permissible norms provokes the appearance of renal failure and neurological disorders up to coma.
A patient with an overdose is shown hardware clarification of blood, symptomatic treatment and close attention from medical personnel.
Antiviral drug analogues
Valacyclovir is available under various brand names. In addition to the original name, you can find such names as:
- “Vairova” - convex oval blue tablets with a dosage of half a gram;
- "Valvir" - white biconvex oblong pills with a marking of 500 and 1000 mg;
- "Valtrex" 0.5 g - oval-shaped tablets with a light core, coated with a thin polymer film;
- "Valtsikon" - smooth rounded white pills of 0.5 g;
- "Virdel" - oblong white capsules of 0.5 g.
All analogues of Valaciclovir, together with the original drug, are taken according to a single scheme. Only a doctor can adjust the dosage based on the results of a kidney examination.
Herpes exists in the body for life. Modern medicine does not yet have the means to promote a complete cure. And although the most important role in the prevention of relapse is given to strengthening immunity, the antiviral drug Valaciclovir is also a very effective measure to combat the symptoms of the disease.
