Valacyclovir
Valacyclovir: instructions for use and reviews
- 1. Release form and composition
- 2. Pharmacological properties
- 3. Indications for use
- 4. Contraindications
- 5. Method of application and dosage
- 6. Side effects
- 7. Overdose
- 8. Special instructions
- 9. Application during pregnancy and lactation
- 10. Use in childhood
- 11. In case of impaired renal function
- 12. Use in the elderly
- 13. Drug interactions
- 14. Analogs
- 15. Terms and conditions of storage
- 16. Terms of dispensing from pharmacies
- 17. Reviews
- 18. Price in pharmacies
Latin name: Valacyclovir
ATX code: J05AB11
Active ingredient: valacyclovir (valaciclovir)
Producer: Ozone LLC (Russia), Drug Technology (Russia), Sintez, JSC (Russia), Izvarino Pharma, LLC (Russia)
Description and photo updated: 28.08.
Prices in pharmacies: from 287 rubles.
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Valacyclovir is an antiviral drug.
Release form and composition
Valacyclovir is available in the form of film-coated tablets: oval biconvex, the core and shell are almost white or white, 1000 mg tablets have a dividing risk on one side (7, 10, 28 or 30 pieces in a blister strip, in a cardboard box 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 packs; 7, 10, 20, 28, 30, 40, 42, 50, 60 or 100 pcs. in a can, in cardboard box of 1 can; each box also contains instructions for the use of Valacyclovir).
1 tablet contains:
- active substance: valacyclovir hydrochloride - 556.2 mg or 1112.4 mg, which corresponds to the content of 500 mg or 1000 mg of valacyclovir;
- auxiliary components: povidone K25, microcrystalline cellulose, magnesium stearate;
- shell composition: titanium dioxide, macrogol 4000, hypromellose.
Pharmacological properties
Pharmacodynamics
Valacyclovir is an antiviral agent. It is an L-valine ester of acyclovir, an analogue of a purine nucleotide (guanine), a specific inhibitor of DNA polymerase (deoxyribonucleic acid polymerase) of herpes viruses. Blocks viral DNA biosynthesis and viral replication.
A substance in the human body under the influence of the enzyme valacyclovir hydrolase is rapidly and completely converted into acyclovir and L-valine. Active acyclovir triphosphate is formed from acyclovir as a result of phosphorylation, which is able to competitively suppress viral DNA polymerase.
The first stage of phosphorylation is carried out under the influence of a virus-specific enzyme (for Varicella zoster, Herpes simplex, Epstein-Barr virus - viral thymidine kinase, which is found only in cells infected with the virus) The selectivity of the drug for cytomegalovirus is due to the fact that phosphorylation is to some extent mediated by the product of the UL97 phosphotransferase gene.
The substance is active against cytomegalovirus, Herpes simplex viruses of types 1 and 2, Varicella zoster, Epstein-Barr and human herpesvirus type 6.
Pharmacokinetics
Valacyclovir is highly absorbed. The substance is quickly and almost completely converted into acyclovir and L-valine.
When 1 g of valacyclovir is taken, the bioavailability of acyclovir is 54% (3–5 times higher than after oral administration of acyclovir).
After taking 3 g of valacyclovir 4 times a day, the AUC value (area under the concentration-time curve) is approximately equal to the AUC of acyclovir when administered intravenously at a dose of 5 mg every 8 hours.
C max (maximum plasma concentration) after a single intake of 1 g of the substance is from 15 to 25 µmol / ml, the time to reach it is in the range of 1.6-2.1 hours; unmetabolized valacyclovir is not detected in plasma after 3 hours. The degree of binding to plasma proteins: valacyclovir - 13-18%, acyclovir - 9-33%.
Acyclovir is widely distributed in body fluids and tissues, including in the fluid of herpetic vesicles, brain, liver, kidneys, lungs, intestines, spleen, muscles, uterus, mucous membrane and vaginal secretions, semen, lacrimal, amniotic and cerebrospinal fluids … The highest concentrations are found in the kidneys, intestines and liver. The substance passes through the placenta and into breast milk.
T 1/2 (half-life) of valacyclovir - less than 30 minutes, acyclovir - from 2.5 to 3.3 hours, in patients with end-stage renal failure - 14 hours, in elderly patients (65 to 83 years) - from 3.3 to 3.7 hours.
Excretion is carried out by the kidneys (45.6%), mainly as acyclovir and its metabolite (9-carboxymethoxymethylguanine), less than 1% is excreted unchanged, as well as through the intestines (47.12%) for 96 hours.
Indications for use
For patients over 12 years old, the use of Valacyclovir is indicated:
- treatment and prevention (including in adults with immunodeficiency) of infectious diseases of the mucous membranes and skin caused by herpes simplex virus [including herpes labialis (Herpes labialis) and newly diagnosed or recurrent genital herpes (Herpes genitalis)];
- prevention of infectious pathologies after transplantation of parenchymal organs;
- prevention of cytomegalovirus infections.
In addition, only adults are prescribed pills for the treatment of herpes zoster (Herpes zoster), including herpes zoster ophthalmic.
Contraindications
- HIV infection with a total CD4 and lymphocyte count of less than 100 in 1 μl;
- age up to 12 years (when prescribed for the purpose of preventing infections caused by cytomegalovirus and diseases after solid organ transplantation);
- age up to 18 years (when prescribed for all other indications; due to insufficient clinical data);
- hypersensitivity to acyclovir or drug components.
Valacyclovir tablets should be taken with caution if there is a risk of dehydration, renal failure, concomitant use of nephrotoxic drugs, during pregnancy and breastfeeding, in old age, in patients with a clinically expressed form of HIV infection.
Valacyclovir, instructions for use: method and dosage
Valacyclovir tablets are taken orally with water, regardless of the meal.
Recommended dosage:
- treatment of infections of the skin and mucous membranes caused by the herpes simplex virus: 500 mg 2 times a day. In case of relapse - within 3 or 5 days, in case of primary herpes - the duration of the course should be extended to 10 days. In case of relapse, it is necessary to start taking the drug in the prodromal period or from the moment the first signs of the disease appear. As an alternative, in the treatment of labial herpes, a double dose of 2000 mg for 1 day with an interval of at least 6 hours is considered effective;
- suppression or prevention of recurrence of infections of the skin and mucous membranes caused by the herpes simplex virus (including in adults with immunodeficiency): immunocompetent patients - 500 mg 1 time per day, adults with immunodeficiency - 500 mg 2 times a day. The duration of the course is 6-12 months, then it is necessary to evaluate the effectiveness of therapy;
- prevention of cytomegalovirus infections and diseases after transplantation (transplantation) of parenchymal organs: 2000 mg 4 times a day, the duration of treatment is 3 months or more. The drug should be taken immediately after transplantation. The dose should be reduced taking into account creatinine clearance;
- treatment of herpes zoster (Herpes zoster) and ophthalmic herpes zoster in adult patients: 1000 mg 3 times a day, course - 7 days.
In patients with impaired renal function, dose adjustment is required.
The dosage regimen for patients with severe renal impairment depends on creatinine clearance (CC):
- therapy of ophthalmic herpes zoster and herpes zoster in immunocompetent adult patients: CC 50 ml / min and above - 1000 mg 3 times a day, CC 30-49 ml / min - 1000 mg 2 times a day, CC 10-29 ml / min - 1000 mg once a day, CC less than 10 ml / min - 500 mg once a day;
- therapy of viral herpes simplex in immunocompetent patients over 12 years of age: CC 30 ml / min and above - 500 mg 2 times a day, CC up to 30 ml / min - 500 mg once a day;
- therapy of labial herpes in immunocompetent patients: CC 50 ml / min and above - 2000 mg 2 times a day, CC 30-49 ml / min - 1000 mg 2 times a day, CC 10-29 ml / min - 500 mg 2 times a day, CC up to 10 ml / min - 500 mg once a day;
- prevention (suppression) of viral herpes simplex in immunocompetent patients over 12 years old: CC 30 ml / min and above - 500 mg once a day, CC up to 30 ml / min - 500 mg once every two days;
- prevention (suppression) of viral herpes simplex in adults with immunodeficiency: CC 30 ml / min - 500 mg 2 times a day, CC up to 30 ml / min - 500 mg once a day;
- prevention of cytomegalovirus infections: CC up to 75 ml / min - 2000 mg 4 times a day, CC 50-75 ml / min - 1500 mg 4 times a day, CC 25-50 ml / min - 1500 mg 3 times a day, CC 10-25 ml / min - 1500 mg 2 times a day, CC up to 10 ml / min or with hemodialysis - 1500 mg once a day. The tablets are taken after the hemodialysis procedure.
The patient needs to ensure the maintenance of an adequate water and electrolyte balance.
With cirrhosis of the liver of mild and moderate severity in adult patients (with preserved synthetic liver function), it is possible to prescribe the drug in a dose of 1000 mg once a day.
Side effects
- on the part of the psyche and nervous system: often - headache; rarely - confusion, dizziness, depression of consciousness, hallucinations; very rarely - psychotic symptoms, agitation, tremor, encephalopathy, ataxia, dysarthria, convulsions, coma;
- from the gastrointestinal tract: often - nausea; rarely - vomiting, abdominal discomfort, diarrhea;
- from the immune system: rarely - anaphylaxis;
- from the blood system and hematopoietic organs: very rarely - thrombocytopenia, leukopenia (more often against the background of reduced immunity);
- from the respiratory system: infrequently - shortness of breath;
- on the part of the hepatobiliary system: very rarely - reversible violations of functional liver tests;
- from the urinary system: infrequently - hematuria (usually with pathological disorders of the kidneys); rarely - functional impairment of the kidneys; very rarely - renal colic, acute renal failure; possibly - an accumulation of crystals of the drug in the lumen of the renal tubules;
- dermatological reactions: infrequently - skin rash, photosensitivity; rarely - itching; very rarely - urticaria, angioedema;
- others: against the background of long-term therapy in high doses (patients with HIV infection) - renal failure, microangiopathic hemolytic anemia, thrombocytopenia (the degree of drug effect has not been established).
Overdose
The main symptoms: vomiting, nausea, acute renal failure, neurological disorders (including hallucinations, confusion, depression of consciousness, agitation, coma). In most cases, the development of such conditions was observed with impaired renal function and in elderly patients who received repeated exceeding the recommended doses of valacyclovir, which is associated with non-compliance with the dosage regimen.
Therapy: the condition of patients should be closely monitored. The elimination of acyclovir from the blood is largely facilitated by hemodialysis; it can be considered the method of choice in the treatment of acyclovir overdose.
special instructions
Treatment with Valacyclovir should be carried out under the close supervision of a physician, this will allow to timely determine the development of undesirable effects and take adequate measures.
The use of valacyclovir from the moment the first signs of relapse appear may have a greater therapeutic effect and avoid the development of a lesion caused by the herpes simplex virus. Symptoms of labial herpes include itching, tingling, and burning.
In order to prevent the development of dehydration, during the period of taking the tablets, it is necessary to drink a sufficient amount of liquid, especially for elderly patients.
Regular determination of creatinine clearance, especially after organ transplantation or engraftment, allows for adequate dose adjustment of valacyclovir and reduces the risk of adverse effects on the part of renal function.
In the presence of symptoms of genital herpes, sexual intercourse without reliable means of barrier contraception is contraindicated, even against the background of antiviral therapy.
Influence on the ability to drive vehicles and complex mechanisms
Taking high doses of valacyclovir often causes the development of side effects, especially from the nervous system, therefore, during the period of treatment, it is recommended to be careful when driving.
Application during pregnancy and lactation
Valacyclovir during pregnancy / lactation is prescribed with caution after assessing the ratio of the expected benefit to the possible risk.
According to the registration records on the outcome of pregnancy in women who took Valacyclovir and other drugs containing acyclovir, there was no increase in the number of birth defects in their children compared to the general population. However, reliable and definite conclusions about the safety of using valacyclovir during pregnancy cannot be made, since only a small number of women who took valacyclovir during gestation are included in the register.
Pediatric use
Contraindication:
- under 12 years of age: when prescribed for the prevention of infections caused by cytomegalovirus and diseases after solid organ transplantation;
- up to 18 years of age: when prescribed for all other indications (due to insufficient clinical data).
With impaired renal function
Valacyclovir is prescribed with caution in patients with renal insufficiency.
Use in the elderly
Valacyclovir for elderly patients is prescribed under medical supervision.
Drug interactions
Since Valacyclovir is excreted unchanged by renal secretion, care must be taken with concomitant therapy with drugs with a similar elimination mechanism. These include: nephrotoxic agents, aminoglycosides, iodinated contrast agents, pentamidine, organic platinum compounds, methotrexate, foscarnet, cyclosporine, tacrolimus.
The risk of an increase in the level of concentration in the blood plasma of each of the drugs or their metabolites increases when taking high doses of valacyclovir per day (4000 mg and more).
Analogs
Valaciclovir analogues are: Valacyclovir Canon, Valvir, Valtsikon, Valtrex.
Terms and conditions of storage
Keep out of the reach of children.
Store at temperatures up to 25 ° C in a dark place.
The shelf life is 3 years.
Terms of dispensing from pharmacies
Dispensed by prescription.
Reviews about Valacyclovir
Reviews of Valacyclovir are mostly positive. Patients note the high efficiency of the drug. The cost is assessed as affordable, especially if there is no need for a long course. The development of side effects is rarely reported.
Price for Valacyclovir in pharmacies
The approximate price for Valacyclovir is 328–467 rubles. (10 tablets) or 1998–2695 rubles. (50 tablets).
Valacyclovir: prices in online pharmacies
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Drug name Price Pharmacy |
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Valacyclovir Canon 500 mg film-coated tablets 10 pcs. 287 r Buy |
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Reviews Valacyclovir Canon 287 r Buy |
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Valacyclovir 500 mg film-coated tablets 40 pcs. 1359 RUB Buy |
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Valacyclovir 500 mg film-coated tablets 50 pcs. 1431 RUB Buy |
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Maria Kulkes Medical journalist About the author
Education: First Moscow State Medical University named after I. M. Sechenov, specialty "General Medicine".
Information about the drug is generalized, provided for informational purposes only and does not replace the official instructions. Self-medication is hazardous to health!
