The mechanism of action of antiviral drugs primarily involves targeting specific stages of the viral life cycle. These drugs may inhibit viral replication, prevent viral entry into host cells, or disrupt the assembly of new viral particles. For example, some antivirals like acyclovir interfere with viral DNA synthesis, while others, such as protease inhibitors, block enzyme activity crucial for viral maturation. By selectively attacking these processes, antiviral drugs help to reduce viral load, alleviate symptoms, and improve patient outcomes during infections, as seen in the treatment of diseases like HIV and influenza.