Treatment of Respiratory Viral 1.pdf

Powered by AI Copilot Here is the rewritten version of your text: Antiviral Drugs 1. Overview Viruses: Obligate intracellular parasites Lack: Cell wall, cell membrane, organelles Symptoms: Appear late in the disease...

Powered by AI Copilot Here is the rewritten version of your text: Antiviral Drugs 1. Overview Viruses: Obligate intracellular parasites Lack: Cell wall, cell membrane, organelles Symptoms: Appear late in the disease course Antiviral Drugs: Virustatic Use: Prophylactic agents 2. Treatment of Respiratory Viral Infections Viruses Involved: Influenza A (variety of animal hosts) Influenza B (humans only) Respiratory Syncytial Virus (RSV) Approach: Preferred: Immunization Alternative: Antiviral drugs (for allergies, outbreaks) Influenza A: Characteristics: Causes pandemics (e.g., H1N1) Surface Proteins: Neuraminidase (N), Hemagglutinin (H) Function: H for attachment, N for release 3. Neuraminidase Inhibitors Examples: Oseltamivir, Zanamivir Activity: Influenza A and B Administration: Timing: Prior to exposure or within 48 hours of symptoms Duration: 5-day course Mechanism of Action (MOA): Inhibit neuraminidase Prevent release of new virions Pharmacokinetics (PK): Oseltamivir: Prodrug, oral, activated by hepatic esterases Zanamivir: Active, inhaled Excretion: Urine Adverse Effects: Oseltamivir: Nausea, vomiting, headache Zanamivir: Respiratory discomfort, caution in airway diseases Resistance: Mutations in neuraminidase enzyme  4. Adamantane Antivirals Examples: Amantadine, Rimantadine Activity: Influenza A only Administration: Prior to exposure or within 48 hours of symptoms Mechanism of Action (MOA): Block M2 proton ion channel Block viral uncoating Pharmacokinetics (PK): Amantadine: Excreted unchanged in urine Rimantadine: Extensive metabolism before urinary excretion Note: High resistance, not recommended 5. Ribavirin Characteristics: Guanosine analogue, broad-spectrum Activity: RSV, HCV (with other drugs) Use: Severe RSV bronchiolitis or pneumonia in children/infants Mechanism of Action (MOA): Inhibits RNA and DNA virus replication Formation of 5’-phosphate derivative, triphosphate derivative Inhibits GTP formation, prevents mRNA capping, blocks RNA- dependent RNA polymerase Pharmacokinetics (PK): Administration: Oral, inhalation (aerosolized for RSV) Excretion: Urine Adverse Effects: Dose-dependent anemia Aerosol: Conjunctival or bronchial irritation Contraindications: Pregnancy, conceiving children for 6 months after exposure 6. Treatment of Hepatic Viral Infections Hepatitis Viruses: A, B, C, D, E Common Chronic Causes: HBV: DNA virus HCV: RNA virus Goals: HBV: Suppress HBV DNA, seroconversion of HBeAg, reduce hepatic transaminase levels HCV: Viral eradication Is there anything else you need help with?