Antivirals

Lisa Vogel studied departmental journalism with a focus on medicine and biosciences at Ansbach University and deepened her journalistic knowledge in the master's degree in multimedia information and communication. This was followed by a traineeship in the editorial team. Since September 2020 she has been writing as a freelance journalist for

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Antivirals (antivirals) are active ingredients that are used to fight viruses. There are several starting points for these antivirals. Which antiviral agent is used always depends on the particular pathogen. Read how antivirals work, what infections they are used for and what side effects to expect!

What are antivirals?

Antivirals (also known as antivirals) 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 multiplying inside such cells. The early application of antivirals in the event of a viral infection can in many cases reduce symptoms, infectivity and also the duration of the illness.

Virostatics are available for external use (e.g. in the form of ointments or plasters) as well as for internal use (e.g. as tablets).

How do antivirals work?

Viruses do not have their own metabolism. They always need a host cell for their reproduction: 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 attack new cells - the whole thing starts all over again.

Antivirals can intervene at various points in this process and thus stop the virus from multiplying or being released. Each antiviral agent has only one specific point of attack and thus its mechanism of action. These possible points of attack include:

• the attachment of viruses to and penetration into a host cell (e.g. amantadine)
• the replication of the virus genome within the host cell (e.g. acyclovir, 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 to form a new virus (e.g. lopinavir)
• the discharge and release of the newly formed viruses from the host cell (e.g. oseltamivir)

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

From the different mechanisms of action of antivirals it can be deduced that the agents can only work when the virus is actively replicating in the body's cells. Antivirals are ineffective against viruses that do not multiply or dormant in the body's cells (latent viruses).

What antivirals are there?

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

• Herpes simplex infections such as cold sores ("cold sores"), genital herpes (genital herpes), herpes-related brain and meningitis (encephalitis, meningitis)
• Shingles (herpes zoster)
• Flu (influenza)
• Human papilloma virus (HPV) infection
• HIV
• Hepatitis B.
• Hepatitis C.
• Cytomegaly

Which antivirals for which virus?

Each antiviral agent specializes in its mechanism of action for certain viruses and therefore usually only works against a certain virus family. Some examples:

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

So-called neuraminidase inhibitors, such as the active ingredient oseltamivir, work in the case of influenza. Neuraminidase is a protein found on the surface of influenza viruses. It ensures that the viruses newly produced by an infected body cell can detach themselves from the cell - in order to then in turn attack new body cells. The antiviral agent oseltamivir inhibits neuraminidase and thus prevents the flu viruses from spreading further in the patient's body. However, this only works if patients take the drug within 48 hours of the onset of symptoms.

Antivirals against coronaviruses?

So far, there is no specifically effective antiviral agent against coronaviruses - not even against the coronavirus type Sars-CoV-2, which is currently circulating around the world. However, researchers are working on developing new antiviral drugs against the Covid-19 pathogen. In addition, one checks whether known antivirals that are used against other diseases also help against Sars-CoV-2.

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

Are there also herbal antivirals?

In addition to antiviral drugs from the laboratory, some natural remedies against viruses have also proven themselves: Some plants have an anti-viral effect and / or support the immune system in the fight against viruses. Examples of such plants are:

• Red coneflower (Echinacea purpurea), available in the form of drops and lozenges.
• Rockrose (Cystus incanus), often part of lozenges.
• Black elder (Sambucus nigra), used for example 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 tea, syrup, in capsules and other ready-made preparations.
• Thyme (Thymus vulgaris), often drunk as a tea or used for gargling, or in the form of ready-made preparations such as cough syrup.
• Bloodroot (Potentilla erecta), also used in the form of tea, gargle solution or ready-made preparations (such as coated tablets).
• Garlic (Allium sativum), used pure or in the form of capsules and other ready-made preparations.

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

Do antivirals require a prescription?

You can obtain light antivirals for external use without a prescription from the pharmacy, e.g. antiviral ointment for cold sores. In contrast, antivirals for internal use (e.g. antiviral tablets) usually require a prescription. The doctor will prescribe the correct antiviral agent after identifying the virus.

Antivirals: side effects

Like all active pharmaceutical ingredients, antivirals can also trigger side effects. Such undesirable effects are most likely to occur with internal use. Depending on the antiviral drug, the following side effects are possible, for example:

• Gastrointestinal complaints
• Flu-like symptoms
• headache
• itching
• Restlessness
• dizziness
• Changes in blood count
• allergic reaction

You can find out from the leaflet which side effects the antivrial agent you are using may have. Your doctor or pharmacist can also provide more detailed information on this.

You should keep this in mind when using antivirals

Use an antiviral drug in exactly the dosage and duration as recommended by your doctor or pharmacist.

Antivirals can interact with other drugs. Therefore, if you habitually take other preparations because of a chronic disease (e.g. diabetes, gout, rheumatoid arthritis), you should always talk to your doctor before using antiviral agents.

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

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

Tags:  laboratory values gpp palliative medicine