Antiviralia

Products

Direct antiviralia are commercially available as drugs in the form of tablets, capsules, solutions, and creams, among others. The first antiviral agent was approved in the 1960s (idoxuridine).

Structure and properties

Antivirala are a large group of drugs and have no uniform chemical structure. However, groups can be formed, such as the nucleoside analogs. These are analogs of DNA building blocks and prodrugs that are activated primarily in infected cells by phosphorylation.

Effects

Antiviralia (ATC J05) are causally and directly active against viruses (antiviral). They interact selectively with viral structures and exert their effects at different stages of viral replication. The exact course of the replication cycle depends on the virus:

  • Attachment (adsorption).
  • Penetration into the cell, fusion
  • Uncoating
  • Reverse transcription
  • Integration into the host genome
  • Propagation of RNA or DNA (replication).
  • Formation of the new virus components (translation)
  • Maturation
  • Release

By affecting these processes, they suppress viral replication and prevent further spread of the pathogens. Typical drug targets of antiviralia are enzymes, other proteins, and nucleic acids. The drugs are usually selective for one virus or a group of related viruses. The large group of nucleoside analogues are derivatives of DNA building blocks which, after phosphorylation, are incorporated into viral DNA as false substrates. This leads to chain termination and thus inhibits DNA polymerase and DNA synthesis. A second approach is to interact with drug targets of the host cells, which are required by the viruses for their replication. However, this usually involves more adverse effects. This mechanism is less common.

Indications

For the prevention and treatment of viral infectious diseases, for example, viral hepatitis, HIV, herpes infections, and influenza.

Dosage

According to the SmPC. For acute infections, therapy must be started as soon as possible after the onset of symptoms to suppress viral replication.

Active Ingredients

The active ingredients can be found under the following drug groups (selection):

  • Antisense therapeutics (cytomegaly).
  • CCR5 antagonists (HIV).
  • Endonuclease inhibitors (influenza).
  • Fusion inhibitors (HIV)
  • Gp120 antagonists (HIV)
  • HCV NS5A inhibitors (hepatitis C).
  • HCV polymerase inhibitors (hepatitis C).
  • HCV protease inhibitors (hepatitis C)
  • HIV protease inhibitors (HIV)
  • Interferons (hepatitis B, C)
  • Integrase inhibitors (HIV)
  • M2 channel blockers (influenza)
  • Monoclonal antibodies (e.g., RSV)
  • Neuraminidase inhibitors (influenza)
  • Nucleoside analogues (herpes viruses, hepatitis).
  • Phosphonic acid derivatives (herpesviruses).
  • Reverse transcriptase inhibitors (HIV, hepatitis).
  • RNA polymerase inhibitors: Favipiravir (influenza, Ebola).

Contraindications

Full precautions can be found in the drug label. Antiviralia should not be used in bacterial infectious diseases, as they are not suitable for their treatment.

Adverse effects

Adverse effects depend on the drugs used. Antiviralia are not completely selective for viral structures and therefore may cause side effects in the organism. As with antibiotics, one problem is the development of resistance, which can occur because of mutations in the viral genome under selection pressure.