Antiviral drugs


Antivirals is the umbrella term for the group of all active ingredients that are effective against viruses. From the word "Antivirals“Its effect is derived from it. It consists of the two parts "virus" and "stasis“ (Greek for standstill) and describes the effects of the drugs. The aim is to prevent the viruses from multiplying further, a so-called Replication stall should enter.

What drugs against viruses are there?

Viruses do not have their own metabolism, but are dependent on the metabolic processes of the host cell. This makes the causal therapy of viral diseases considerably more difficult and one has to look into the replication cycles (Multiplication cycles) intervene.
Numerous other drugs can be used for symptomatic therapy, which treats the symptoms but not the causes: anti-inflammatory agents, painkillers and antipyretic drugs can treat the consequences of the viral infection. However, they do not stop the viruses themselves.

You may also be interested in this topic: Viral infection

Normally, the body manages to use its own immune system to fight the viruses and fight the infection. But not all patients have the body's immune system working so well that they can successfully fight off the infection. Then drugs against viruses become necessary, since they are currently the only option for causal therapy, i.e. therapy that combats the causes.
They inhibit the virus from replicating by inhibiting different stations in their replication process.
In recent years, the number of antiviral substances has increased, which is due, among other things, to the intensive fight against HIV infection. Several new antiviral drugs are approved each year. Nevertheless, there are still no active ingredients that kill viruses sustainably.


The active ingredient acyclovir is mainly used to treat infections with herpes simplex virus and varicella zoster viruses. These mainly include infection with herpes in the genital area, cold sores (blisters on the lip) and shingles. Acyclovir is mainly used at home as film-coated tablets or cream. Frequent administration is necessary for the active ingredient.

You can find more interesting information about the active ingredient here: Acyclovir


The active ingredient valaciclovir is converted to aciclovir in the body. It has the advantage that it does not have to be taken as often as acyclovir. Valaciclovir is currently only available in tablet form.
It is also used to treat infections with herpes viruses and to prevent disease with the CMV virus (cytomegalovirus) after a kidney transplant. Common herpes infections for which valaciclovir is used include shingles, as well as an infection of the eyes, mucous membrane or genital region with herpes simplex viruses.


Famciclovir is converted to penciclovir in the body. This must be converted one more time until the resulting active ingredient penciclovir triphosphate is created.
Famciclovir is mainly used to treat a herpes infection of the eye or genital area. Famciclovir is also used for shingles (herpes zoster). It is available in tablet form and is taken two to three times a day regardless of meals.


Brivudine is converted into an active ingredient in the body. The active ingredient is used when an infection with the varicella zoster virus is reactivated, which manifests itself as shingles (herpes zoster). As a rule, one tablet is taken once a day, regardless of the meal. Care should be taken to ensure that it is taken at the same time each day.

You can find more interesting information about the active ingredient here: Brivudine

Effect / drug groups

Antiviral agents can be differentiated according to their mode of action. They prevent viruses from multiplying at different stages. To prevent this mechanism from occurring, one must first consider the stages that virus replication goes through.

First, the viruses bind to the surface of the host cell (human cells). When the virus dockes, a protein molecule on the surface of the virus binds to a specific receptor on the host (absorption). In the further course of the process, the virus penetrates the cell, depending on the type of virus, either via fusion between the virus envelope and the cell membrane or by infiltration via newly formed pores in the host cell's membrane.
When the virus has been absorbed into the host cell, it continues its genetic information (Genome) free. This process is called "uncoating" designated. The viral genome is then propagated in several intermediate steps.
Finally, the virus particles are assembled (maturation) and the finished viruses are released.

Medicines can be applied to all of these nodes and prevent the virus from multiplying. This results in the following groups of active substances: On the one hand, entry inhibitors, because they prevent the virus particles from docking on the host's cell membrane (Ancriviroc, aplaviroc).
Then penetration inhibitors, these serve to prevent penetration into the host cell and thus also prevent the "uncoating“ (Amantadine, pleconaril).
It is followed by the huge group of inhibitors of reproduction. These include some subgroups that prevent the synthesis of nucleic acids or proteins. They include

  • DNA polymerase inhibitors
  • DNA / RNA polymerase inhibitors
  • RNA polymerase inhibitors
  • Reverse transcriptase inhibitors
  • Inosine monophosphate dehydrogenase inhibitors
  • Protease inhibitors
  • Integrase inhibitors
  • Antisense oligonucleotides
  • Helicase-primase inhibitors

However, this subdivision is very confusing and difficult to understand. They are suitable in their effectiveness against the enzymes which are required for replication.
Other inhibitors that prevent the composition of the virus, such as the drug Bevirimat against HIV, are also important.
Finally, there are neuraminidase inhibitors that prevent the release of the newly produced viruses. Examples of this are oseltamivir and zanamivir, drugs against the flu viruses.

Side effects

Some side effects may occur when taking anti-virus medication

The range of side effects of this group of drugs is just as large as the number of different active ingredients and in addition to type of application also depending on the administered dose. Generally one can say that the local and applied externally Substances well tolerated and the side effects are only limited to the area of ​​application. The orally or intravenous The active ingredients administered have effects on the whole body and mostly dissolve nausea, a headache or diarrhea out.
Especially active ingredients against several pathogens effective trigger side effects more often. Active ingredients that have the liver metabolized and broken down because they can be even more harmful for patients with liver damage. The special side effects of the individual active ingredients can be found in the Instruction leaflets can be read.

Medicines against viruses for colds

Mostly colds are caused by viruses that are over Droplet infections are transmitted and make the affected person sick. In the case of colds, in most cases no anti-virus medication necessarybecause they are through simple Home remedies for colds and light antipyretic and anti-inflammatory drugs heal again.
In addition to his cold, it should also have a strong feeling of illness and fever a doctor should be consulted. He can use a quick flu test to determine whether Flu viruses are responsible. In this case, drugs for the virus can be prescribed and taken.

Read more about the here Difference Between Flu and Cold and the Therapy for colds.

Herpesvirus drugs

Acyclovir is often prescribed for cold sores.

Human herpes viruses cause serious illness in humans. The best known is the somewhat more widespread cold sore, which is mainly caused by the herpes simplex viruses type 1 and 2. In addition to these herpes viruses, there are numerous others that can cause very serious diseases.

What all herpes viruses have in common is that they contain double-stranded DNA that is produced by a virus’s own enzyme (DNA polymerase) can be replicated. It is precisely at this enzyme that the drugs for the treatment of herpes start. The active ingredients inhibit the viral DNA polymerase and thus prevent the viruses from replicating further.
They are administered as a preliminary stage and then activated and effective in the body through a short metabolic process. Overall, there are several different active ingredients that can be used against herpes, the main representatives being acyclovir and valaciclovir.

Valaciclovir is a so-called ProdrugAfter ingestion, it is converted to acyclovir in the body and then takes effect. In general, both substances can be taken orally as a tablet, administered as an infusion through a vessel or applied to the skin as a cream.
In the case of severe herpes infections, it is necessary to administer the drug through a vessel because this is where the drug is most effective.
In general, acyclovir is a well-tolerated antiviral drug, but in higher doses it can be harmful to the kidneys.

There are also the drugs penciclovir and famciclovir: Penciclovir is suitable for topical application on the skin to treat herpes. Famciclovir, on the other hand, can also be taken as a tablet, is then activated in the gastrointestinal tract to penciclovir and thus effective against the herpes virus.
Famciclovir should not be used during pregnancy and breastfeeding. Occasionally, dizziness, itching, and dry skin from the application will occur.

The drug brivudine is given as a tablet. In addition to its action against the herpes virus, changes in the blood count can sometimes occur, but these are reversible.This medication should also not be taken during pregnancy or breastfeeding; in addition, the doctor should pay attention to possible interactions with any cytostatic therapy when prescribing it.

Compatibility with the pill

The compatibility of Antiviral drugs and the Contraception pill can be influenced in two possible ways: On the one hand, the compatibility with the pill can be influenced by the Dismantling of the active ingredients in the liver are influenced, on the other hand the pill is over the Intestinal wall absorbed. That is why it is important that the Gut flora intact is.
At severe diarrhea or Vomit shortly after taking the pill is its effect not guaranteed. In general, antivirals have no effect on intestinal bacteria, which is why the intestinal function should not be impaired. However, if diarrhea or vomiting occurs as side effects, the pill may lose its effectiveness.
It is recommended in the Leaflet the respective drug against viruses can be read in more detail. When applying antivirals on the skin should no tolerance issues occur with the pill. Likewise, it is not expected that the pill will lose its effectiveness.

Compatibility with alcohol

The general principle that Alcohol and medication not well tolerated and therefore should not be taken at the same time, also applies to anti-virus drugs. Many of the substances are about the liver activated, rebuilt or dismantled. The liver is busy with this task. Alcohol is also broken down by the liver and depending on Extent of consumption (lots of alcohol, high blood alcohol levels) the alcohol remains in the body long after you actually drink it and the liver is busy breaking it down.
Both substances therefore stress the liver, so consuming them at the same time is harmful and can lead to too unexpected side effects to lead. Both substances cannot be adequately metabolized and thus remain in the body longer.

In addition, it is possible that the effects of alcohol or other drugs are caused by the anti-virus drugs reinforced becomes. Overdoses can occur more quickly, the effects of alcohol can be less controllable. Consequently, it should be done as much as possible while taking antivirals abstained from alcohol become.

Eye drops against viruses

An infection of the eyes by viruses occurs mainly in infections with herpes viruses. These infections are very painful and require immediate, effective therapy. The active ingredient trifluidin is only suitable for use against herpes infections in and on the eye. In the form of eye drops, it inhibits viral replication. It also leads to redness of the eyes, itching and increased tearing. This medication must also not be used during pregnancy or breastfeeding, or after eye surgery.

Another active ingredient that can be used for topical application to the eye against viral infections is ganciclovir or its prodrug valganciclovir. It is particularly used for corneal inflammation caused by herpes viruses. These active substances can aggressively affect blood formation and cause confusion. In addition, they are extremely harmful to unborn children, which is why they should not be used during pregnancy and breastfeeding.

Shingles medication

The shingles (Herpes zoster) is the second disease that follows an infection with the chickenpox virus in old age, because the chickenpox virus persists in the body after the rash in childhood and nests in cranial nerves or nerve roots of the spinal cord. If the immune defense is weakened, these viruses can be reactivated and migrate along the nerves to the skin. Shingles then occurs in the supply area of ​​the corresponding nerves.

In addition to the skin, the eyes or even the brain can also be affected. The main goal of symptomatic therapy for shingles is to relieve pain. This is achieved by taking pain relievers and applying skin creams. Antiviral drugs are almost always prescribed to prevent the virus from multiplying further.

Therapy with the special medication should be started as soon as the symptoms appear (2-5 days). Antiviral drugs for shingles are: acyclovir, valaciclovir, famciclovir and brivudine. They ensure faster healing of the symptoms and reduce the risk of painful conditions after the shingles have healed.

The active ingredient brivudine is contained in the drug Zostex®.

Read more about this under: Zostex®