Acyclovir – a modern drug for the treatment of herpes, as well as some other viral diseases. Acyclovir has a direct antiviral effect, which means that it acts directly on the viruses themselves, preventing them from multiplying.
The mechanism of the antiviral effect of the drug is that the active substance contained in the preparation enters the virus-infected cells. Once in the cells, the virus begins to multiply in them, using nucleotides present in the cell to synthesize the viral genome.
The structure of acyclovir is similar to the formation of guanine present in the cells. Viral enzymes modify acyclovir to acyclovir triphosphate, which is structurally identical to deoxyguanosine triphosphate, typically included in the sequence of viral DNA. The “unsuspecting” viral protein embeds a Trojan horse into its DNA chain. And in vain, since acyclovir triphosphate makes it impossible to replicate the virus. This stops its reproduction and dramatically facilitates the body’s immune forces fight against viral particles.
It should be noted that the active substance of the drug does not affect the genetic apparatus of the cell itself and does not contribute to the emergence of mutations. This can be argued from the results of numerous tests on animals, and on the practice of using the drug in humans. Therefore, in this regard, the drug is entirely safe.
The described method of combating viruses in its time was a novelty in the world of medicine, and the developers of the drug were awarded the Nobel Prize. And still, Acyclovir remains the most effective remedy for herpes viruses, despite the emergence of new antiviral drugs.
What viruses protects the drug from? Unfortunately, the scope of the medicine is limited only to a particular class of viruses, namely, the herpesvirus family. These include type 1 and type 2 herpes simplex viruses, varicella-zoster virus (Varicella Zoster), cytomegalovirus that causes a cytomegalovirus infection, and Epstein-Barr virus, which causes some tumors and blood diseases. Therefore, one should not listen to the opinion of those who offer treatment with Acyclovir for any viral infections, such as influenza and even AIDS.
The impact of the drug on various viruses of the family varies. The most terrible drug for herpes simplex viruses, a little weaker effect on the varicella-zoster virus and even worse on the cytomegalovirus and Epstein-Barr virus.
Indications for use
First of all, the drug treats diseases caused by the herpes simplex virus. These are herpes that appears on the face, first of all, around the lips, and on the mucous membranes, including the mucous membranes of the eyes, as well as in the area of the anus and genitals.
Diseases caused by the Varicella zoster virus include chickenpox and shingles. Illnesses caused by cytomegalovirus and Epstein-Barr virus are also treatable with the drug. However, their therapy requires larger doses than in the treatment of herpes simplex.
Herpes is one of the most common infectious diseases. Its main symptoms are rashes in the lips, face, and eyes. Sometimes rashes appear in the genital area. As a rule, rashes strongly itch and cause painful sensations.
Statistics show that more than 90% of the world’s population is infected with the herpes simplex virus. However, the manifestation of herpes is not observed at all. What is the reason? The fact is that immunity in healthy people usually inhibits the spread of the virus. However, in some cases, the privilege may be weakened, and then we meet with the manifestations of herpes.
The concentration of acyclovir in the cerebrospinal fluid is 50% of the mass in the blood plasma. Plasma protein binding is relatively low (9–33%). Acyclovir is mainly excreted unchanged through the kidneys. Renal clearance of acyclovir is significantly higher than creatinine clearance, which indicates that its removal is carried out not only by glomerular filtration but also by tubular secretion.
What can reduce herpes immunity:
infectious diseases (acute respiratory infections, flu)
changes in hormonal levels (for example, during pregnancy)
If these causes lead to the activation of the virus, then antiviral therapy is prescribed with the help of the drug.
Often there are cases when the drug is used for other purposes, for example, for the treatment of boils, acne, other rashes and dermatitis, not associated with herpes viruses. There will be no benefit to the body. Therefore, before you begin treatment, you should clarify the diagnosis – herpes or shingles, with a specialist. It should also be remembered that the use of antibiotics for herpes is also devoid of meaning.
The drug is available in various dosage forms:
acyclovir tablets, 200 or 400 mg
The question may arise; which dosage form is optimal? The attending physician must decide this. However, it should be noted that in the case when it comes to rashes on the skin, it is best to use a cream or ointment, from which the active substance enters the reproduction sites of the virus directly. If you use Acyclovir tablets, then due to the low bioavailability of the drug in the blood gets only a small amount. This means that the effectiveness of the tool will be lower.
Acyclovir – although an inexpensive, but quite a dangerous drug. Therefore, Acyclovir tablets are sold in pharmacies only by prescription. The only exceptions are creams and ointments.
The drug has several analogs. The most famous of them is Zovirax. It is a drug that has the same composition. However, it is of import origin, and therefore its price is somewhat higher.
The drug has some side effects. Allergic reactions to the components of the medicine, headache, dizziness, gastrointestinal dysfunction – nausea, diarrhea, vomiting can occur.
In no case cannot combine the drug intake with alcohol. The fact is that the drug is metabolized in the liver with the help of the same enzymes as alcohol. Therefore, if you take Acyclovir and drink at the same time, this will lead to the fact that both substances will accumulate in the blood and, as a result, to poisoning. Temporary changes in the blood picture and liver enzyme activity are infrequent. Individual cases of headaches, fatigue, exhaustion, drowsiness, insomnia, and breathing difficulties were observed.
Acyclovir has several contraindications. First of all, the drug penetrates the placental and blood-brain barriers, passes into breast milk. Therefore, it is not recommended for use during pregnancy. When prescribing the medication to pregnant and lactating mothers, the doctor must weigh the pros and cons. It is also not advised to give tablets to children under three years.
Instructions for use and dosage
When taking tablets, Acyclovir should use the instructions for use, which is supplied with the drug, or instructions of the attending physician.
Usually, Acyclovir 200 mg tablets must be taken with herpes simplex five times a day. Between receptions, a break of 4 hours should be observed (at night – 8 hours). With chickenpox and shingles, the dose is increased four times – up to 800 mg.
Children have prescribed the drug from their weight – 20 mg/kg. In this case, the drug is taken four times a day for five days.
The usual course of treatment is five days, with genital herpes, the period is increased to 10 days. Prevention of herpes is carried out by taking 400 mg of the drug every 12 hours.
The maximum permissible daily dose is 2 g. The absorption of a substance into the blood does not depend on food. Therefore, Acyclovir tablets can be taken before and after meals.
The body’s ability to remove the active substance from the blood is limited, so it is necessary to follow the dosage in order not to be poisoned strictly.
When using a cream or ointment, the medicine is spread with a thin layer on the affected area. It should be remembered that a thick layer of lotion will not increase the therapeutic effect, but only lead to the waste of the drug.
Inside usage. Adult patients for the treatment of primary infections and recurrences of Herpes simplex of the skin and mucous membranes – 1 table. (200 mg) Acyclovir 5 times a day. The duration of treatment is usually five days. In severe cases, more prolonged therapy may be required. In patients with a significantly weakened immune system (for example, after a bone marrow transplant) or patients with insufficient intestinal absorption, a single dose increase to 400 mg or IV administration of the drug is necessary. To suppress the recurrence of Herpes simplex infection in patients with a healthy immune system – 1 table. Acyclovir (200 mg) 4 times a day or 2 tablets. 2 times a day.
For the prevention of Herpes simplex infection in patients with weak immune systems – 1 table. (200 mg) Four times a day. In patients with severely impaired immune defenses (for example, during bone marrow transplantation) or patients with insufficient intestinal absorption, a single dose can be increased to table 2. appointment.
Elderly patients: in elderly patients, the rate of total elimination of acyclovir is reduced. During therapy with high oral doses of the drug, it is necessary to ensure sufficient fluid intake in the patient. In cases of impaired renal function, special attention should be paid to reducing the dose. The decision to use the drug in patients with limited renal function is a doctor.