Zovirax is an antiviral drug developed for the treatment and prevention of infections caused by herpes viruses. The drug effectively inhibits the reproduction of herpes simplex and varicella-zoster viruses, helping to reduce the severity of symptoms, accelerate healing of affected areas and reduce the risk of recurrences. Its action is aimed at blocking viral replication, which makes Zovirax an important tool in the therapy of diseases such as herpetic rashes on the skin, genital herpes and shingles. The drug is available in different dosage forms, allowing the treatment to be tailored to the specific needs of the patient.
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Dosage | Package | Per Item | Per Pack | Order |
400 mg |
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800 mg |
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The trade name of the drug is Zovirax. This is the registered name under which the drug is known in medical practice and is available in the pharmacy network.
The international nonproprietary name is acyclovir. It denotes the active active ingredient and is used in pharmacology at the international level.
Zovirax is available in several forms: 200 mg, 400 mg and 800 mg tablets packed in blisters of 5, 10 or 25 pieces; cream 5% in tubes of 2 g, 5 g or 10 g; eye ointment 3% in tubes of 4.5 g; powder for preparing a solution for infusion of 250 mg in bottles. Tablets have white color, cream and ointment - white homogeneous consistency, and the powder is intended for dilution in medical conditions.
The main active component is acyclovir. One tablet contains 200 mg, 400 mg or 800 mg acyclovir; 1 g cream - 50 mg; 1 g eye ointment - 30 mg; one vial of powder - 250 mg.
Tablets include lactose monohydrate, microcrystalline cellulose, sodium starch glycolate, povidone, magnesium stearate. The cream contains propylene glycol, cetyl alcohol, white petroleum jelly, poloxamer 407, purified water. Eye ointment - white petroleum jelly. Powder for infusion - sodium hydroxide and water for injection (after dilution).
Acyclovir, the active substance of Zovirax, is a synthetic analog of purine nucleoside with pronounced antiviral action. After penetration into infected cells, acyclovir is phosphorylated by viral thymidine kinase to acyclovir monophosphate and then by cellular enzymes to acyclovir triphosphate. This active form competitively inhibits viral DNA polymerase, preventing the synthesis of new viral DNA, which stops viral replication. The drug is highly selective to viral enzymes, minimally affecting human DNA, which ensures its safety.
Zovirax is active against herpes simplex virus types 1 and 2 (HPV-1, HPV-2), varicella-zoster virus (VZV), as well as partially against Epstein-Barr virus and cytomegalovirus. When applied topically (cream, ointment), it quickly relieves itching, pain and inflammation, accelerating the healing of rashes. When administered systemically (tablets, infusions), the drug reduces the viral load and prevents the spread of infection. The effect is noticeable after 1-3 days with topical treatment and after 3-7 days with systemic therapy.
Acyclovir when taken orally is partially absorbed from the gastrointestinal tract, with a bioavailability of 15-30%. Maximum concentration in plasma is reached in 1.5-2 hours. When administered intravenously, bioavailability is 100%, and peak concentration is observed immediately after infusion. When applied topically (cream, ointment), systemic absorption is minimal (less than 0.5%). Food intake does not affect absorption.
Acyclovir is weakly bound to blood plasma proteins (9-33%). The volume of distribution is about 0.7 l/kg, which ensures penetration into the skin, mucous membranes, lungs, kidneys and cerebrospinal fluid. The drug passes through the blood-brain barrier and placental barrier, and is also excreted in breast milk.
Acyclovir is minimally metabolized in the liver (10-15%). The main metabolite, 9-(carboxymethoxymethoxymethyl)guanine (CMMG), is formed with the participation of alcohol dehydrogenase and aldehyde dehydrogenase enzymes and has no significant activity.
Half-life of acyclovir is 2.5-3 hours during oral and intravenous administration. The drug is excreted mainly through kidneys (about 85-90% in unchanged form) by tubular filtration and tubule secretion. Complete excretion takes about 24 hours, but in renal insufficiency this period increases.
Zovirax is prescribed for the treatment of the following conditions:
The drug is effective in controlling symptoms and preventing complications.
The use of Zovirax is prohibited in:
With caution prescribe in neurological disorders, hepatic insufficiency, pregnancy.
Zovirax tablets are taken orally, drinking water (100-150 ml), regardless of meals. Cream is applied in a thin layer on the affected areas 5 times a day every 4 hours. Eye ointment is placed in the conjunctival sac 5 times a day. Infusion solution is prepared and administered intravenously slowly (1 hour) by medical personnel.
Tablets: for herpes of the skin and mucous membranes - 200 mg 5 times a day for 5 days; for shingles - 800 mg 5 times a day for 7 days; prophylaxis - 200 mg 4 times a day. Cream: 5 times a day for 4-10 days. Infusions: 5-10 mg/kg every 8 hours for 5-7 days.
Tablets: 20 mg/kg (maximum 800 mg) 4-5 times daily for 5 days. Cream: as in adults. Infusions: 250 mg/m² every 8 hours for children older than 3 months.
In renal insufficiency: creatinine clearance 25-50 ml/min - 800 mg 3 times a day; 10-25 ml/min - 800 mg 2 times a day. In hepatic insufficiency correction is usually not required.
Possible adverse reactions include:
The side effects are more often mild and reversible.
Doses above 20 g (tablets) or 100 mg/kg (infusions) may cause nausea, convulsions, renal failure, and confusion.
Stop administration, call a doctor. Gastric lavage (for tablets), give activated charcoal. Hemodialysis is required for infusions.
Zovirax has no significant effect on the metabolism of other drugs. Probenecid and cimetidine slow down the excretion of acyclovir, increasing its concentration. Nephrotoxic drugs increase the risk of renal impairment.
Alcohol does not affect efficacy but may increase dizziness. Food does not alter absorption.
Zovirax is used in pregnancy only on strict indications; lactation should be stopped due to penetration into milk.
The drug may cause dizziness, which requires caution when driving.
In the elderly, the dose is adjusted in case of impaired renal function. In children under 2 years of age tablets are not used; infusions - from 3 months.