Pharmacological action Zovirax (Acyclovir)
Antiviral agent. Virus-infected cells thymidine kinase converts acyclovir actively through a series of sequential reactions in the mono-, di-and triphosphate of acyclovir. The latter interacts with the viral DNA polymerase and incorporated into DNA, which is synthesized for new viruses. Thus, a “defective” viral DNA, which leads to suppression of replication of the new generations of viruses.
Acyclovir is active against Herpes simplex virus types 1 and 2, the virus Varicella zoster, Epstein-Barr virus and cytomegalovirus.
Pharmacokinetics Zovirax (Acyclovir)
If ingestion bioavailability of 15-30%. Widely distributed in tissues and body fluids. Plasma protein binding is 9-33%. Metabolized in the liver. T1 / 2 at intake – 3.3 hours, with a / in the introduction – 2.5 hours excreted in urine, in small amounts – in the feces.
Statement Zovirax (Acyclovir)
For systemic use (oral and / in): infections caused by Herpes simplex virus types 1 and 2 and Varicella zoster; prevention of infections caused by viruses Herpes simplex and Varicella zoster (including patients with lowered immunity) in the combined therapy in patients with severe immunodeficiency (including the clinical presentation of HIV infection) and in patients undergoing bone marrow transplantation, prevention of cytomegalovirus infection after bone marrow transplantation.
For topical use in ophthalmology: keratitis and other eye damage caused by the virus Herpes simplex.
For external use: infections of the skin caused by Herpes simplex virus and Varicella zoster.
Dosage regimen Zovirax (Acyclovir)
Into adults and children over 2 years – 200-400 mg 3-5 times / day if necessary – to 20 mg / kg (up to 800 mg per dose) 4 times / day. In children under 2 years are used in a dose equal to half the adult dosage. Duration of treatment – 5-10 days. In renal insufficiency, correction is recommended dosing regimen.
In / drip in adults and children over 12 years – 5-10 mg / kg, the interval between doses – 8 hours for children aged 3 months to 12 years – 250-500 mg/m2 body surface, the interval between injections – 8 hours for infants dose is 10 mg / kg, the interval between injections – 8 hours
In renal insufficiency must be corrected dosing regimen.
Locally and externally applied 5 times / day. The dose and duration of treatment depend on the evidence and applied the dosage form.
The maximum dose for adults with / in the introduction – 30 mg / kg / day.
Side effect Zovirax (Acyclovir)
Ingestion: nausea, vomiting, diarrhea, abdominal pain, skin rash, headache, dizziness, fatigue, decreased concentration, hallucinations, drowsiness or insomnia, fever, rarely – hair loss, transient increase in blood levels of bilirubin, urea , creatinine, liver enzymes, lymphocytopenia, eritropeniya, leukopenia.
With / in the introduction: acute renal failure, crystalluria, encephalopathy (confusion, hallucinations, agitation, tremors, seizures, psychosis, somnolence, coma), phlebitis or inflammation at the injection site, nausea, and vomiting.
When applied topically: a burning sensation at the site of application, surface punctate keratitis, blepharitis, conjunctivitis.
For exterior use: at the point of application may be a burning sensation, skin rash, itching, peeling, erythema, dry skin in contact with mucous membranes – the inflammation.
Contraindications Zovirax (Acyclovir)
Hypersensitivity to acyclovir and valacyclovir, with a / in the introduction – lactation (breastfeeding).
Pregnancy and breastfeeding Zovirax (Acyclovir)
The application of acyclovir during pregnancy is possible in cases where the intended benefits to the mother outweighs the potential risk to the fetus.
The use of acyclovir is contraindicated during lactation (excreted in breast milk).
In experimental studies in animals showed that acyclovir crosses the placental barrier.
Cautions
We do not recommend use in severe renal impairment.
Please note that the application of acyclovir may develop acute renal failure due to precipitate formation of crystals of acyclovir, which is especially likely during rapid / in the introduction, the simultaneous use of nephrotoxic drugs in patients with impaired renal function and lack of water stress.
When applying acyclovir to monitor renal function (determining the level of blood urea nitrogen and creatinine in blood plasma).
Treatment of elderly patients should be a sufficient increase in water stress and under the supervision of a physician, because in these patients increases the half-life of acyclovir.
In the treatment of genital herpes should avoid sex or use condoms, because use of acyclovir does not prevent transmission of the virus partners.
Acyclovir is in the form of dosage forms for topical use should not be applied to mucous membranes of the mouth, eyes, vagina.
Drug Interactions Zovirax (Acyclovir)
With simultaneous use of probenecid decreases the tubular secretion of acyclovir, and thereby increases the plasma concentrations and elimination half-life of acyclovir.
With the simultaneous use of acyclovir with nephrotoxic drugs increases the risk of nephrotoxicity (especially in patients with impaired renal function).
Enhancing acyclovir seen with concomitant administration of immunostimulants.
When mixing the solutions should be considered an alkaline reaction to acyclovir in / introduction (pH 11).
