Valtrex is a powerful drug, which contains valacyclovir. It is widely used for the treatment and prevention of infections caused by viruses (especially shingles, herpes simplex, recidivous genital herpes, labial herpes and Epstein-Barr virus). Better known acyclovir is an active metabolite of valacyclovir, so valacyclovir is a prodrug. Valtrex coated tablets are not suitable for the treatment of bacterial infections.
Valtrex coated tablets are effective for the treatment of viral diseases caused by Epstein-Barr virus, Human herpesvirus 5, Herpes simplex virus type 1 and type 2, and Varicella zoster virus. The medicine can be used for prevention of recurrent infections of skin and mucosae caused by Herpes simplex virus. It can also be used to prevent cytomegalovirus infection caused by organ transplantation.
Mechanism of action
After an oral administration, the absolute bioavailability of Valtrex coated tablets is (54,5±9,1)% and it is independent of food intake. After absorption under the influence of hepatic enzyme valacyclovir-hydrolase, valacyclovir is almost completely converted to acyclovir and valine. It violates the replication of the virus cells, preventing it from multiplying. Cmax is reached after 1-2 hours after ingestion. About 95% of drug is excreted in the urine.
Contraindications and precautions
In any case, do not use Valtrex coated tablets, if you have an allergic reaction to valacyclovir, acyclovir and other components of the drug.
You should use Valtrex coated tablets with caution, if you have AIDS, HIV infection, renal and hepatic failure, if you are pregnant or breast-feeding. Valtrex coated tablets are not recommended for use by children. Elderly patients should increase water intake during the period of treatment.
Adverse effects and the dosage
If you have any allergic reactions especially anaphylaxis and Stevens-Johnson syndrome, you should immediately seek medical help. The drug was generally well tolerated by patients. However, it has some adverse effects such as stomach-ache, sickness, diarrhea, hepatitis, acute renal failure, pain in the kidney area, thrombocytopenia, headache, dyspnea, confusion, fatigue, tachycardia, hypertension, dyspnoea, coma, hallucinations, photosensitivity, alopecia, erythema, swelling of the face.
Warnings,the dosage depends on the nature and severity of the disease and must be administered by your doctor. It is independent of food intake. The medicine should be used with the first symptoms of the disease. For the treatment of Herpes zoster the medicine is used at a dosage of 1000 mg (one 1000mg Valtrex coated tablet) three times a day for 7 days. For the treatment of Herpes simplex virus drug is used at a dosage of 500 mg (a half of 1000mg Valtrex coated tablet) two times a day for 3-5 days. For the prevention of herpes infection medication is recommended at a dose of 500 mg 1-2 times a day. The duration of treatment is 4-12 months. Patients with renal and hepatic disease require correction of dosage.