Study Notes for Chapter 7: Drugs for Viral and Retroviral Infections

Chapter 7: Drugs for Viral and Retroviral Infections

Pathophysiology of Viruses and Retroviruses

  • Viruses:

    • Cannot replicate on their own; require host cells.

    • Utilize the host cell's machinery to synthesize proteins and nucleic acids (DNA and RNA).

  • Retroviruses:

    • A subset of viruses that reverse-transcribe RNA into DNA within host cells, integrating into the host genome.

Common Antiviral Drugs

Herpes Simplex Viral Infections

  • Acyclovir (Zovirax):

    • Action: Suppresses replication of HSV-1, HSV-2, and VZV.

    • Forms: Oral, topical, parenteral.

    • Side Effects: Nausea, diarrhea, headache.

  • Patient Education:

    • Inform patients that treatment does not cure the infection but helps manage symptoms.

    • Emphasize the importance of early administration for better outcomes.

Influenza Infections

  • Oseltamivir (Tamiflu):

    • Action: Reduces duration of illness; effective against influenza A and B.

    • Side Effects: Nausea, vomiting.

  • Zanamivir (Relenza):

    • Action: Also reduces duration; inhalation route.

    • Side Effects: Diarrhea, nausea, sinusitis.

Cytomegalovirus and Respiratory Syncytial Virus

  • Ganciclovir (Cytovene):

    • Action: Treats CMV infections.

    • Side Effects: Bone marrow toxicity.

  • Ribavirin (Virazole):

    • Action: Treats RSV; significant teratogenic effects.

    • Forms: Inhalation for hospitalized infants.

Hepatitis B and C

  • Hepatitis B Treatment:

    • Drugs: Lamivudine, tenofovir, telbivudine, alpha-interferon.

    • Side Effects: Fatigue, nausea, headache.

  • Hepatitis C Treatment:

    • Drugs: Interferon, ribavirin, simeprevir, sofosbuvir.

    • Side Effects: Anemia, headache, flu-like symptoms.

Reverse Transcriptase Inhibitors and Protease Inhibitors

  • Types of Reverse Transcriptase Inhibitors:

    • Block virus replication early in the life cycle; essential in HIV treatment.

    • Examples: Zidovudine (Retrovir), Tenofovir (Viread).

  • Protease Inhibitors:

    • Prevent maturation of viral particles; act later in the viral life cycle.

    • Examples: Indinavir (Crixivan), Ritonavir (Norvir).

  • Patient Education:

    • Stress adherence to medication regimen to maintain immunity and slow disease progression.

    • Counseling on potential side effects like pancreatitis and peripheral neuropathy.

Entry Inhibitors, Fusion Inhibitors, and Integrase Inhibitors

  • Entry Inhibitors & Fusion Inhibitors:

    • Prevent HIV from entering host cells.

  • Integrase Inhibitors:

    • Block integrase enzyme; prevent viral DNA integration into host cell DNA.

    • Example: Raltegravir (Isentress).

Key Characteristics of Antiviral Drugs

  • Must enter infected cells to work.

  • Interfere with viral nucleic acid synthesis and regulation.

  • Some stimulate the immune system to enhance response.

General Nursing Implications

  • Drugs do not cure viral infections; they suppress and manage symptoms.

  • Encourage reporting of adverse reactions and adherence to storage instructions.

  • Immunocompromised patients require additional protective measures, such as avoiding impure water.

Conclusion

  • Understanding the properties and functions of antiviral medications is crucial in managing viral infections effectively and ensuring proper patient education.