Antiviral Medications Mechanism and Side Effects

Antiviral Medications: Mechanism of Action, Clinical Indications, and Side Effects

• Antiviral medications can be categorized by their target: neuraminidase inhibitors, ATP analogues, guanosine analogs, viral DNA/RNA polymerase inhibitors, and HIV reverse transcriptase inhibitors.

Neuraminidase Inhibitors

• Oseltamivir and Zanamivir are neuraminidase inhibitors that prevent the release of new viruses from infected cells.
• Treatment and prevention of influenza A and B.
• Beginning therapy within 48 hours of symptom onset may shorten the duration of illness.
• Side effects: Details not readily available.

Cap-Dependent Endonuclease Inhibitors

• Baloxavir inhibits the influenza virus's cap-dependent endonuclease, which is essential for viral replication.
• Treatment and prevention of influenza A and B.
• Beginning therapy within 48 hours of symptom onset may shorten the duration of illness.
• Side effects: Details not readily available.

ATP Analogues

• Remdesivir mimics ATP, being incorporated into viral RNA, causing premature termination of RNA synthesis and inhibiting viral replication.
• Treatment for COVID-19 requiring hospitalization.
• Side effects: Details not readily available.

Guanosine Analogs

• Acyclovir, Famciclovir, and Valacyclovir target Viral DNA polymerase, reducing side effects targeting healthy cells.
• Used to treat: HSV-induced mucocutaneous lesions, Encephalitis, Prophylaxis in immunocompromised patients, Patients with recurrent or severe infections, Herpes zoster
• Side effects include: obstructive crystalline nephropathy and acute kidney injury (if not adequately hydrated).

Viral DNA/RNA Polymerase Inhibitors

• Ganciclovir targets viral kinase (UL97) to form 5'-monophosphate, then subsequently triphosphate forming by cellular kinases to inhibit viral DNA polymerase.

• Effective against CMV infections, especially in patients who are immunocompromised.

• Side effects include: renal toxicity, myelosuppression (thrombocytopenia, neutropenia, leukopenia).

• Foscarnet directly inhibits viral DNA polymerase, RNA polymerase, and HIV reverse transcriptase.

• Used to treat: CMV retinitis in immunocompromised patients and Acyclovir-resistant HSV.

• Side effects include: Nephrotoxicity, multiple electrolyte abnormalities can lead to seizures.

• Cidofovir inhibits viral DNA polymerase directly, disrupting viral DNA synthesis.

• Used to treat: CMV retinitis in immunocompromised patients.

• Side effects include: Nephrotoxicity; should be co-administered with probenecid and IV saline to decrease toxicity.

Antiviral Medications: Mechanisms of Action, Clinical Indications, and Side Effects

• Antiviral medications target different steps of the viral replication cycle to help treat or prevent viral infections.
• Neuraminidase inhibitors like oseltamivir and zanamivir target the enzyme neuraminidase, which prevents the release of newly formed viruses from infected cells.
• Baloxavir inhibits the influenza virus's cap-dependent endonuclease, blocking the "cap-snatching" process essential for viral mRNA synthesis.
• Remdesivir mimics ATP, incorporating itself into viral RNA and causing premature termination of RNA synthesis, inhibiting viral replication.
• Guanosine analogs like acyclovir, famciclovir, and valacyclovir are activated by thymidine kinase, targeting viral DNA polymerase and minimizing harm to healthy cells.
• Ganciclovir relies on viral kinase (UL97) for initial phosphorylation, leading to inhibition of viral DNA polymerase, proving effective against CMV and other viruses.
• Foscarnet directly inhibits viral DNA polymerase, RNA polymerase, and HIV reverse transcriptase by binding to the pyrophosphate-binding site, halting DNA elongation.
• Cidofovir directly inhibits viral DNA polymerase, disrupting viral DNA synthesis without requiring phosphorylation by viral kinase.
• While the provided table offers a starting point, consulting the full document is crucial for gathering complete information on specific side effects and clinical details for each antiviral drug.

This quiz covers the mechanisms of action, clinical indications, and side effects of various antiviral medications. It includes details on neuraminidase inhibitors, cap-dependent endonuclease inhibitors, and ATP analogues. Test your knowledge on their applications in treating influenza and other viral infections.