Acyclovir

General characteristics. Structure:

Active agent: acyclovir of 200 mg.

Excipients: sugar milk; potato starch; aerosil; polyvinylpirrolidone middlemolecular; calcium stearate.

Pharmacological properties:

Pharmacodynamics. The acyclovir has high specificity concerning the Herpes simplex (HSV) virus, including HSV type 1 and HSV type 2, the Varicella zoster (VZV) virus, Epstein-Barre's (EBV) virus and a cytomegalovirus (CMV). In cellular cultures the acyclovir shows the greatest activity concerning HSV-1, further in process of decrease: HSV-2, VZV, EBV and CMV. The acyclovir gets directly into the cells infected with a virus. The cells infected with a virus produce a virus thymidinekinase which phosphorylates an acyclovir to a monophosphate acyclovir. Besides, activity of a virus thymidinekinase in relation to an acyclovir is much higher, than action on it cellular enzymes (in the infected cells concentration of an acyclovir of monophosphate is 40-100 times higher). Further phosphorylation by cellular enzymes leads an acyclovir triphosphate to education, being extremely active and selection inhibitor of a DNA polymerase of viruses. Possibly the inhibition mechanism an acyclovir triphosphate of synthesis of DNA consists that it is the substrate allowing to carry out the communication 3–5 necessary for extension of a chain of DNA for this enzyme. Thus the premature break of a chain of DNA is made.

Pharmacokinetics. At oral administration the acyclovir is only partially soaked up in intestines. After purpose of a dose of 200 mg of 5 times in days of Cmax of an acyclovir in a blood plasma makes 3,2 µmol (0,7 mkg/ml), Cmin) — 1,8 µmol (0,4 mkg/ml).
Concentration of an acyclovir in cerebrospinal fluid makes 50% of concentration in a blood plasma. Linkng with proteins of plasma rather low (9–33%). The acyclovir is generally brought out of an organism in not changed look through kidneys. The renal clearance of an acyclovir is significantly higher than clearance of creatinine that indicates that its removal is carried out not only by means of glomerular filtering, but also by tubular secretion.
The only metabolite found in urine is 9-karboksimetoksimetilguanin (10–15% of the appointed dose).

Indications to use:

- treatment of primary and recurrent infections of skin and mucous, caused by the Herpes simplex virus;
- suppression of a recurrence of the infections caused by the Herpes simplex virus in patients with normal and weakened by immune system;
- primary and recurrent infections caused by the Varicella zoster virus.

Route of administration and doses:

Inside. To adult patients for treatment of primary infections and a recurrence of Herpes simplex of skin and mucous — 1 tab. (200 mg) of the Acyclovir of 5 times a day. Treatment duration usually makes 5 days. In serious cases more prolonged treatment can be required. At patients with considerably the weakened immune system (for example after bone marrow transplantation) or at patients with insufficient intestinal absorption increase in a single dose up to 400 mg or in/in administration of drug is necessary. For suppression of a recurrence of the infection caused by Herpes simplex in patients with normal immune system — 1 table. An acyclovir (200 mg) 4 times a day or according to 2 tab. 2 times a day. For prevention of an infection of Herpes simplex at patients with weak immune system — 1 tab. (200 mg) 4 times a day. At patients with heavy disturbances of a host defense (for example at bone marrow transplantation) or at patients with insufficient intestinal absorption the single dose can be increased to 2 tab. by reception.

Children: for treatment of the infection caused by Herpes simplex and prevention of this infection against the background of the weakened host defense, children are more senior than 2 years receive the same dose, as adults; 2 years — a half of a dose for adults are younger.

Elderly patients: at elderly patients the speed of the general removal of an acyclovir decreases. During therapy it is necessary to provide with high peroral doses of drug sufficient intake of liquid in the patient's organism. In cases of disturbance of renal function special attention should be paid on a dose decline. The decision on use of drug for patients with bounded renal function is made by the doctor.

Features of use:

Efficiency of treatment by that will be higher, than earlier it is begun. At patients with an immunodeficiency at repeated repeated courses of treatment resistance of viruses to an acyclovir sometimes forms.

Side effects:

Dermatological reactions: an enanthesis which disappears after drug withdrawal are in rare instances observed.

Gastrointestinal frustration are in certain cases possible: nausea, diarrhea and abdominal pains; quickly taking place disorders of neurologic character are in some cases possible: dizziness, decrease in concentration of attention, a hallucination and drowsiness, mainly at patients with reduced renal function; very seldom temporary changes in a picture of blood and activity of enzymes of a liver meet. Separate cases of headaches, fatigues, exhaustions, drowsiness, sleeplessness and difficulty of breath were observed.

Interaction with other medicines:

Probenetsid slows down removal of an acyclovir.

Contraindications:

Hypersensitivity to an acyclovir or any other component of drug.

Use at pregnancy and feeding by a breast
At pregnancy appointment is possible only in exceptional cases at strict assessment of a ratio of need of use of drug and possible risk. It is not necessary to appoint to nursing mothers.

Overdose:

There are no data.

Storage conditions:

In the dry, protected from light place, at a temperature not above 25 °C.
To store in the place, unavailable to children.

Issue conditions:

According to the recipe

Packaging:

In a blister strip packaging of 10 pieces; in a pack cardboard 2 packagings.