Home Medicines Antivirals: effect, application, side effects

Antivirals: effect, application, side effects

by Josephine Andrews
Published: Last Updated on 225 views

Antivirals (virustatics) are active ingredients that are used to combat viruses. There are different starting points for these antiviral agents. Which antiviral is used always depends on the respective pathogen. Read how antivirals work, which infections they are used for and what side effects you have to reckon with!

What are antivirals?

Antivirals (also virustatics) are antiviral drugs, i.e. agents that inhibit viruses . For example, they prevent the pathogens from docking onto the body’s own cells or from being able to multiply inside such cells. The early use of antivirals in the event of a viral infection can in many cases reduce symptoms, infectivity and the duration of the disease.

Antivirals are available for external use (e.g. in the form of ointments or patches) and for internal use (e.g. as tablets).

How do antivirals work?

Viruses do not have their own metabolism. They always need a host cell to reproduce: They penetrate the cell and release their genetic material, which forces the cell to produce new viruses according to these foreign instructions. These then leave the host cell and can in turn infect new cells – the whole thing starts all over again.

Antivirals can intervene in this process at various points and thus stop the virus multiplication or release. Each antiviral only has a specific point of attack and thus mechanism of action. These possible points of attack include:

  • the attachment of the viruses to and entry into a host cell (e.g. amantadine )
  • the replication of the viral genome within the host cell (e.g. aciclovir, lamivudine)
  • the production of the individual virus components based on the instructions in the virus genome (e.g. fomivirsen)
  • the assembly of the various virus components into a new virus (e.g. lopinavir)
  • the ejection and release of the newly formed viruses from the host cell (e.g. oseltamivir)

If a virus changes due to a mutation (eg protein change), the point of attack for a previously effective antiviral can be lost. Doctors then speak of a resistance of this pathogen. Similarly, bacteria can become resistant to certain antibiotics.

From the various mechanisms of action of antivirals it can be deduced that the agents can only work if the virus is actively multiplying in the body cells. Antivirals are ineffective against viruses that do not multiply or lie dormant in the body cells (latent viruses).

What antivirals are there?

Antivirals are available against various – but by no means all – viral diseases, such as:

Which antivirals for which virus?

Every antiviral is specialized with its mechanism of action on certain viruses and is therefore usually only effective against a certain virus family. Some examples:

In many cases, doctors prescribe the antiviral drug acyclovir against herpes infections (e.g. cold sores, shingles, herpes-related meningitis, cytomegalovirus disease). It is built into the genetic material (DNA) of the virus by virus enzymes, which stops the virus from multiplying. The antivirals famciclovir and valaciclovir are also used against herpes infections.

In the case of flu (influenza), so-called neuraminidase inhibitors act like the active ingredient oseltamivir. Neuraminidase is a protein on the surface of influenza viruses. It ensures that the viruses newly produced by an infected body cell can detach themselves from the cell – and then in turn infect new body cells. The antiviral oseltamivir inhibits neuraminidase and thus prevents the further spread of the flu virus in the patient’s body. However, this only works if patients take the drug within 48 hours of the onset of symptoms.

Antivirals against corona viruses?

So far, there is no antiviral drug that is specifically effective against corona viruses – not even against the Sars-CoV-2 type of corona virus that is currently circulating around the world. However, researchers are working on developing new antiviral drugs against the Covid 19 pathogen. It is also being checked whether known antivirals that are used against other diseases also help against Sars-CoV-2.

There is currently only one such antiviral that can be tried with reservations to treat seriously ill Covid 19 patients – remdesivir. This antiviral agent was originally developed against Ebola . However, research has shown that it can also shorten the duration of illness in Covid-19, at least in some patients.

Are there also herbal antivirals?

In addition to antiviral medicines from the laboratory, some natural remedies against viruses have also proven their worth: some plants have an antiviral effect and/or support the immune system in the fight against viruses. Examples of such plants are:

  • Coneflower ( Echinacea purpurea), available in the form of drops and lozenges.
  • Rockrose (Cystus incanus), often an ingredient in lozenges.
  • Black elder (Sambucus nigra), for example used as a tea or in drops and juices.
  • Ginger (Zingiber officinale), also used as a tea, but can also be found in capsules and as a tincture.
  • Licorice (Glyzyrrhiza glaba), used as a tea, syrup, in capsules and other ready-made preparations.
  • Thyme ( Thymus vulgaris), often drunk as a tea or used for gargling , or used in the form of ready-made preparations such as cough syrup.
  • Tormentil (Potentilla erecta), also used in the form of tea, gargle solution or ready-made preparations (such as dragees).
  • Garlic (Allium sativum), used pure or in the form of capsules and other ready-to-use preparations.

Essential oils from various medicinal plants such as eucalyptus and tea tree oil can also be used to support viral infections. They are used externally, for example when inhaled .

Do antivirals require a prescription?

Light antivirals for external use are available without a prescription in the pharmacy, eg antiviral ointment against cold sores. In contrast, antivirals for internal use (e.g. antiviral tablets) usually require a prescription. The doctor prescribes the right antiviral after identifying the virus.

Antivirals: side effects

Like all active ingredients in medicines, antivirals can also cause side effects. Such undesirable effects are most likely to occur with internal use. Depending on the antiviral, the following side effects are possible:

  • Gastrointestinal complaints
  • Flu-like symptoms
  • headache
  • itching
  • restlessness
  • dizziness
  • blood count changes
  • allergic reaction

The package leaflet tells you what side effects the antiviral medicine you are taking can have. Your doctor or pharmacist can also provide you with more detailed information on this.

You should keep this in mind when using antivirals

Use an antiviral in exactly the dose and for the duration recommended by your doctor or pharmacist.

Antivirals can cause drug interactions. Therefore, if you habitually take other medications because of a chronic condition (eg, diabetes, gout , rheumatoid arthritis), you should always consult your doctor before using antivirals.

Pregnant and breastfeeding women should also consult a doctor before using antivirals.

If you develop side effects such as allergic reactions while using antivirals, you should speak to your doctor immediately. If necessary, the doctor can adjust the dosage or prescribe a different preparation.

You may also like

Leave a Comment