Itching, painful blisters in the mouth area - every third German had ever had to fight with cold sores. Means of choice against this herpes is then usually a cream with the active ingredient acyclovir, whereby the symptoms can be alleviated. But acyclovir also works against other diseases caused by herpes viruses - such as shingles or genital herpes. We explain what you need to know when taking acyclovir and what side effects may occur.
Mode of action: inhibition of virus multiplication
Aciclovir is a so-called nucleoside analogue. This means that in its chemical structure it resembles a building block of the DNA of the herpes virus. When the virus replicates in an affected human cell and duplicates its DNA, the acyclovir molecule can be incorporated instead of the "right" building block. This then leads to the virus multiplication being interrupted.
In this way, the active ingredient can relieve and shorten the course of herpes infections. Aciclovir acts against the herpes simplex virus type 1 and type 2 (HSV-1 and HSV-2) and against the varicella-zoster virus, which also belongs to the group of herpes viruses.
Application of acyclovir
Acyclovir is used in the following diseases caused by herpes viruses:
- Cold sores (herpes labialis)
- Genital herpes (genital herpes)
- Shingles (herpes zoster)
- Corneal inflammation of the eye
- Brain inflammation (encephalitis)
In addition, acyclovir can be used in heavily immunocompromised patients - such as after organ transplantation - for the prevention of HSV infections. Rarely does the drug also be used to treat chickenpox (varicella) in immunocompromised individuals.
Aciclovir as an ointment
Aciclovir ointment is used for relieving pain and itching in cold sores and is available over the counter in the pharmacy. The cream should be applied to the affected area every four hours until the bubbles become crusty. The duration of treatment is usually five to a maximum of ten days. In addition, an aciclovir ointment can be used to aid in the treatment of a genital herpes.
There is a special treatment for the treatment of corneal inflammation caused by herpes viruses eye ointmentwhich must be prescribed by the ophthalmologist. During treatment, an ointment strip of about one centimeter in length is usually added to the lacrimal sac every four hours. The duration of treatment depends on the course of the disease - after healing of the inflammation, the ointment should be continued for at least three days.
Dosage of acyclovir
Depending on the disease to be treated, acyclovir can be administered in various dosage forms and dosages: In the form of tablets With 200, 400 or 800 milligrams of active ingredient, acyclovir is used in genital herpes and shingles and in severe cases of corneal inflammation. Please note the dose and use of your doctor's order or the package leaflet!
Genital herpes and corneal inflammation are usually taken three to four times a day 400 milligrams of acyclovir, whereas in shingles usually a higher dose of up to 4,800 milligrams per day to six divided doses is required. The duration of treatment is usually seven to ten days - but it is important that the therapy is started as soon as possible after the onset of symptoms.
Acyclovir as prophylaxis
In particular, patients with severely weakened immune systems, where there is an increased risk of herpes infection, can be treated with acyclovir preventively. In addition, prophylactic use of acyclovir in patients with recurrent, severe genital herpes may be considered. The dose is usually between 400 and 1,600 milligrams per day.
Infusion therapy in severe diseases
In severe conditions, such as encephalitis caused by herpes viruses, acyclovir may be given as an infusion. Even with severe painful genital herpes or severe complications such as pneumonia in chickenpox, infusion therapy with acyclovir may be considered.
Herpes infections in immunocompromised patients are also commonly treated with acyclovir infusions. In contrast to the use in the form of tablets infusions are usually much more effective - but usually a hospital stay is necessary.
Contraindications and precautions
Aciclovir should not be used if you are hypersensitive to the active substance. Caution should be exercised in patients with renal impairment, as aciclovir is excreted via the kidney. In case of impaired kidney function, delayed release of acyclovir may occur, which is why a lower dosage is usually required in these cases.
Side effects with acyclovir
Aciclovir is a relatively well-tolerated drug - side effects usually occur only at high dosages or during infusion therapy. Because then crystals can form from the active ingredient in the urine and thereby damage the kidney. Therefore, you should drink adequately when taking acyclovir.
In addition, the following side effects may occur:
- Allergic reactions such as rash
- Nausea and vomiting
- Headache or dizziness
- Confusion, impaired consciousness or hallucinations
- Alteration of the blood picture as well as the liver values and renal values
- Burning, irritation or reddening of the skin or conjunctiva during topical treatment with aciclovir ointment or cream.
- Irritation of veins at the infusion site and inflammation - especially in case of accidental leakage of the infusion into the tissue.
For a detailed list of possible side effects, please see the package leaflet.
Interactions of the drug
Interaction with drugs may occur when you are taking acyclovir medication that affects your kidney activity - for example, probenicid (used to treat gout), cimetidine (used to reduce stomach acid), or theophylline (for respiratory diseases such as asthma) ).
In addition, the simultaneous treatment with the active substances mycophenolate mofetil and ciclosporin (to suppress the immune system after transplantation) may lead to interactions with acyclovir. Therefore always inform your doctor about all medications that you need to take regularly!
Aciclovir in pregnancy and lactation
In animal studies, the use of acyclovir during pregnancy has led to malformations of the fetus. However, there is no evidence that the drug has adverse effects on the unborn child in humans. In the absence of adequate studies, the use of acyclovir in pregnancy should only be carried out after careful consideration of the benefits and risks.
However, it is known that acyclovir passes into breast milk. Therefore, acyclovir should not be used during breastfeeding. If treatment with acyclovir is necessary during breastfeeding, it may be possible to take a breastfeeding pause for the duration of the treatment.