Antiviraal

Antiviraal is a term used to refer to agents that treat infections caused by viruses. Antiviraal drugs work by inhibiting viral replication, blocking entry into host cells, or preventing maturation and release of new viral particles. Since viruses rely on host cells, antivirals aim to target viral processes selectively, but toxicity and drug interactions can occur.

Antiviraal drugs are grouped by mechanism and target. Nucleoside and nucleotide analogs, such as acyclovir, ganciclovir, lamivudine, zidovudine, remdesivir, and sofosbuvir, mimic natural nucleotides and, after activation by viral or cellular kinases, terminate viral nucleic acid synthesis. Protease inhibitors, used for HIV (ritonavir, lopinavir, atazanavir) and for certain coronaviruses (nirmatrelvir in combination therapy), inhibit viral proteases required to process viral polyproteins. Neuraminidase inhibitors for influenza (oseltamivir, zanamivir) prevent release of new virions. Polymerase inhibitors, including RdRp inhibitors such as favipiravir and remdesivir, disrupt viral RNA synthesis. Entry and fusion inhibitors, such as maraviroc (CCR5 antagonist) and enfuvirtide (gp41 blocker), prevent viruses from entering host cells. Integrase inhibitors for HIV (raltegravir, dolutegravir) block integration of viral DNA into the host genome.

Monoclonal antibodies and interferons are also used in specific contexts as antiviral strategies, including prophylaxis or treatment for certain viruses. The effectiveness and spectrum of antiviral drugs vary by virus; resistance can emerge with monotherapy, which has led to combination regimens in diseases like HIV and HCV. Ongoing research seeks broader-spectrum and host-targeted approaches to improve outcomes.