There are few effective antiviral drugs due to the parasitic nature of viruses. Since viruses hijack host cell machinery and sometimes can even integrate into a host genome, targeting viruses is difficult because targeting will often affect the host cell as well. This leads to toxic side effects with dangerous consequences for patients.
Because of this, the general strategy for antivirals is to target steps in a virus life cycle that are specific only to that virus.
Commonly targeted steps due to specificity would include:
- virus attachment to cell receptor
- protease cleavages
- virus assembly and budding
- virus specific RNA replication or DNA synthesis
Classes of Antiviral Drugs
Viral Genome Synthesis Inhibitors
- nucleoside analogs (AZT)
Viral Protein Maturation Inhibitors
- peptide mimics (ritonavir)
Entry and Uncoating Inhibitors
- ion channel blockers (amantadine)
Viral Spread Inhibitors
- neuraminidase inhibitors (Tamiflu)