Gaviran

Geviran is a systemic antiviral drug.

Indications Guevirana

Applicable for:

• elimination of skin infections and infectious processes on the mucous membranes caused by the herpes simplex virus (this includes the genital form of herpes of the primary or recurrent type);
• suppression (prevention of relapses) of infectious processes caused by the herpes simplex virus in people with normal immune parameters;
• prevention of infections caused by the herpes simplex virus in individuals with immunodeficiency;
• elimination of infectious pathologies caused by the varicella-zoster virus (shingles and chickenpox).

Release form

Released in tablets, 10 pieces inside a blister pack. In a separate pack - 3 blister plates with tablets.

Pharmacodynamics

Acyclovir is an artificial analogue of a purine nucleoside that inhibits in vitro and in vivo the replication processes of viruses from the Herpes category that are dangerous to the human body: common herpes types 1 and 2, as well as the varicella-zoster virus.

The effect of acyclovir on slowing down the replication of the viruses described above is quite selective. There is no substrate for internal thymidine kinase inside cells uninfected by the disease, as a result of which the toxic effect of the substance on cells becomes insignificant. But TK, which have a viral nature (HSV and VZV viruses), phosphorylate the active component of the drug into a monophosphate derivative (an analogue of a nucleoside), and it is then phosphorylated by cellular enzymes into di- and tri-phosphate acyclovir. The latter element is a substrate for the DNA polymerase of the virus, helping it to enter the DNA of the virus, which completes the binding of the DNA chain of the virus and inhibits the process of its replication.

Long-term use of acyclovir or repeated courses in people with severe immunodeficiency can provoke the emergence of viral strains that are resistant to acyclovir. Within most of the noted strains with reduced sensitivity, there is some deficiency of the TK element, but in addition, strains have been described in which the viral TK or DNA polymerase is altered.

In vitro tests have shown the ability to form HSV strains with reduced susceptibility. It is unknown whether there is a relationship between the presence of in vitro acyclovir susceptibility of the herpes virus and the drug response to therapy.

Pharmacokinetics

Part of acyclovir is absorbed from the gastrointestinal tract. The average equilibrium peak concentration level when taking the drug in a dosage of 200 mg every 4 hours is 3.1 μmol/l (or 0.7 μg/ml), and the similar minimum level is 1.8 μmol/l (or 0.4 μg/ml). When taking the drug in a dosage of 400 or 800 mg every 4 hours, the equilibrium average peak values reach 5.3 μmol/l (or 1.2 μg/ml), as well as 8 μmol/l (or 1.8 μg/ml), and the minimum values are 2.7 μmol/l (or 0.6 μg/ml), as well as 4 μmol/l (or 0.9 μg/ml).

The half-life of the substance in plasma is approximately 2.9 hours. Most of the drug is excreted unchanged in urine. The clearance rates of acyclovir inside the kidneys are much higher than the similar values of CC, which allows us to conclude that tubular secretion and glomerular filtration are involved in the excretion of the drug with urine. The main breakdown product of acyclovir is 9-carboxymethoxymethylguanine, excreted in urine in the amount of approximately 10-15% of the dose taken.

Taking 1 g of probenecid 1 hour before taking acyclovir prolongs the half-life of the latter by 18% and increases the AUC in plasma by 40%.

The half-life of the drug from plasma is 3.8 hours.

In individuals with chronic renal failure, the half-life of the active component of the drug is 19.5 hours. During hemodialysis procedures, this figure decreases to 5.7 hours. During dialysis, plasma values of the substance decrease by 60%.

The level of acyclovir in the cerebrospinal fluid is approximately 50% of its plasma level. The synthesis of the substance with plasma protein is quite weak (about 9-33%), due to which there is no competitive displacement of the component by other drugs from the synthesis site.

Dosing and administration

The Geviran tablet should be swallowed whole with water. If the medicine is used in large doses, it is necessary to monitor the body's hydration indicators.

For adults.

When eliminating infectious processes caused by the herpes simplex virus, it is necessary to take the medicine in a dosage of 200 mg 5 times a day, observing approximately a 4-hour interval between doses (except for the period at night). The period of therapy lasts 5 days, but in case of severe primary infectious disease it can be extended.

People with severe immunodeficiency (for example, after a bone marrow transplant) or with reduced intestinal absorption are allowed to double the dosage of the drug to 400 mg or administer the appropriate dosage intravenously.

The course of therapy should be started as soon as possible after the infection has occurred. In case of recurrent herpes, it is optimal to start therapy during the prodromal period or after the first symptoms of skin lesions have appeared.

In the prevention of relapses (the so-called suppressive treatment) of infectious pathologies caused by the herpes simplex virus, people with healthy immunity need to take the drug in the amount of 200 mg four times a day, observing 6-hour intervals between doses. There is also a more convenient regimen - twice a day use of 400 mg of Geviran, observing a 12-hour interval.

A treatment regimen with a reduction in dosage to 200 mg taken three times a day (8-hour intervals) or twice a day (12-hour intervals) will also be effective.

In some patients, a noticeable improvement in condition is observed when using a daily dose of 800 mg.

To determine possible changes in the natural course of the pathology, treatment is interrupted periodically (with an interval of six months to a year).

To prevent the occurrence of infectious diseases associated with the herpes simplex virus, people with immunodeficiency are required to take the drug in a dosage of 200 mg, four times a day at intervals of 6 hours.

The duration of such prophylaxis depends on the duration of the risk period.

When treating herpes zoster and chickenpox, the drug should be taken in a dosage of 800 mg 5 times a day at intervals of 4 hours (excluding nighttime). The therapy period lasts 1 week.

People with severe immunodeficiency (for example, after a bone marrow transplant) or with reduced intestinal absorption are recommended to use Geviran in a dosage form intended for intravenous injections.

For children.

When eliminating or preventing infectious diseases caused by the herpes simplex virus, for children who suffer from immunodeficiency (over 2 years of age), dosages similar to those for adults are used.

When treating chickenpox in children over 6 years old, take 800 mg of the drug four times a day. Children 2-6 years old should take 400 mg of the drug four times a day. The course duration is 5 days.

To calculate the dosage more accurately, it is necessary to take into account the child's weight - 20 mg/kg per day (but not more than 800 mg per day). The daily dose is divided into 4 separate doses.

People with kidney failure.

Caution is required when used in people with renal insufficiency. It is necessary to maintain the required level of hydration within the body.

During the treatment and prevention of infectious pathologies caused by the herpes simplex virus in people with severe renal failure (with CC values less than 10 ml/minute), it is necessary to use a dosage of 200 mg (taken twice a day with an interval of about 12 hours between doses).

During treatment of infectious diseases caused by the varicella-zoster virus (shingles and chickenpox) in people with significantly reduced immunity: in case of severe renal failure (with CC values less than 10 ml/minute), take 800 mg twice a day at intervals of approximately 12 hours. In case of moderate renal failure (CC values within 10-25 ml/minute), take 800 mg three times a day at intervals of approximately 8 hours.

Use Guevirana during pregnancy

Postmarketing testing of drugs containing acyclovir has found that pregnant women taking the drug developed abnormalities. The results of these tests showed that there was no increase in the incidence of birth defects in children whose mothers used acyclovir compared to the general population. No association could be established between the use of acyclovir by pregnant women and the occurrence of birth defects in newborns.

The use of acyclovir is permitted only in cases where the likely benefit to the woman outweighs the risk of adverse reactions in the fetus.

During lactation, the substance should be used with caution, taking into account the possible risks to the baby.

Contraindications

Contraindications include: intolerance to acyclovir with valacyclovir or other components of the drug, as well as children under 2 years of age.

Side effects Guevirana

Using the medicine may cause the following side effects:

• reactions of the lymph and systemic blood flow: development of thrombocytopenia or anemia, as well as a decrease in the number of leukocytes;
• immune disorders: occurrence of anaphylactic reactions;
• Mental problems and nervous system reactions: the appearance of tremors, headaches, hallucinations, convulsions and dizziness. In addition, there are feelings of confusion, agitation, drowsiness, and psychotic manifestations. Dysarthria, encephalopathy, ataxia and a comatose state also develop. Such signs are often temporary and usually occur in people with functional renal disorders or other factors favorable for the development of pathologies;
• problems with the functioning of the respiratory system: development of suffocation;
• reactions of the gastrointestinal system: the appearance of abdominal pain, nausea, diarrhea and vomiting;
• disorders in the hepatobiliary system: development of jaundice or hepatitis, as well as a transient increase in bilirubin levels or liver transaminase activity;
• dermatological reactions: the appearance of rashes or itching, as well as the development of urticaria, photophobia, Quincke's edema and accelerated alopecia of the generalized type. Since the cause of the development of the latter disorder can be various pathologies and the use of different drugs, it is impossible to say with certainty that alopecia is caused by the use of acyclovir;
• renal and urinary disorders: pain in the kidneys, increased serum urea and creatinine levels, and acute renal failure. Kidney pain may be caused by crystalluria or renal failure. It is necessary to monitor the patient's hydration levels. Functional renal disorders often resolve after restoring fluid balance in the body or after reducing the dosage of the drug or stopping it;
• systemic manifestations: increased temperature or feeling of fatigue.

Overdose

The substance acyclovir is partially absorbed from the gastrointestinal tract, but its single use in a dosage of up to 20 g does not lead to intoxication. Sometimes, in the case of taking the drug for 7 days, the following manifestations of overdose occurred: from the gastrointestinal tract - vomiting with nausea, and from the nervous system - a feeling of confusion and headaches. Such neurological disorders as the appearance of hallucinations, convulsions, a feeling of excitement or confusion, as well as a state of coma, were also observed in the case of overdose after using the drug in the form of an injection.

When taking the drug in a large dose, it is necessary to monitor the patient for the development of signs of intoxication. If they appear, symptomatic therapy is required. The hemodialysis procedure helps to accelerate the excretion of the active component of the drug from the blood, so it is allowed to use it in case of poisoning.

Interactions with other drugs

Acyclovir is excreted mainly unchanged via the renal tubules. Combination with drugs that are metabolized in the body via the same pathway may result in increased plasma acyclovir levels.

Cimetidine with probenecid can increase the AUC of acyclovir, and also reduce its clearance in the kidneys.

A similar increase in plasma levels of acyclovir with its inactive breakdown product, mycophenolate mofetil (an immunosuppressant used after organ transplantation), has been observed when these drugs were used concomitantly. However, since acyclovir has a wide range of action, no dosage adjustment is required.

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Storage conditions

Geviran should be kept in a place where sunlight and moisture do not penetrate, and in addition, inaccessible to small children. Temperature conditions - no more than 25 ° C.

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Shelf life

Geviran can be used for a period of 3 years from the date of manufacture of the medicine.