Antiviral Drugs
Antiviral drugs are medications designed to treat viral infections by inhibiting the development and replication of viruses. They target various stages of the viral life cycle to prevent progression of infection.
Classification
- 1. Respiratory viral infection – Amantadine, Oseltamivir, Zanamivir
- 2. Hepatic viral infection – Adefovir, Boceprevir, Telaprevir
- 3. Herpes virus infections – Cidofovir, Penciclovir
- 4. HIV infections – Abacavir, Tenofovir
Pharmacodynamics
- Amantadine – Inhibits the viral M2 protein, blocking uncoating of influenza A virus.
- Oseltamivir – Neuraminidase inhibitor; prevents release of newly formed influenza A/B viruses from infected cells.
- Boceprevir – Protease inhibitor targeting NS3/4A of Hepatitis C; inhibits polyprotein cleavage and viral replication.
- Cidofovir – Nucleotide analog; inhibits viral DNA polymerase, causing chain termination.
- Abacavir – NRTI; blocks reverse transcriptase in HIV, preventing RNA-to-DNA conversion.
- Tenofovir – NRTI; inhibits reverse transcriptase, blocking HIV replication.
Side Effects
- Common: Nausea, vomiting, diarrhea, headache, dizziness, skin rash, fatigue
- Severe:
- Kidney toxicity – esp. with Cidofovir, Tenofovir
- Liver toxicity – hepatitis risk
- CNS symptoms – hallucinations, seizures (notably Amantadine)
- Bone marrow suppression – anemia, leukopenia, thrombocytopenia
- Hypersensitivity – Stevens-Johnson syndrome, especially with Abacavir