Antiviral Agents

Viruses That Respond to Antiviral Therapy

• Influenza A and some respiratory viruses
• Herpes viruses
• Cytomegalovirus (CMV)
• Human immunodeficiency virus (HIV) that causes acquired immune deficiency syndrome (AIDS)
• Some viruses that cause warts and certain eye infections

Antivirals Across the Lifespan

Characteristics of Common Viruses

• Viral replication
  • A virus cannot replicate on its own
    • It must attach to and enter a host cell
    • It then uses the host cell’s energy to synthesize protein, DNA, and RNA
• Viruses are difficult to kill because they live inside our cells
  • Any drug that kills a virus may also kill our cells

Stages of Virus Replication

Characteristics of Antiviral Drugs

• Able to enter the cells infected with virus
• Interfere with viral nucleic acid synthesis and/or regulation
• Some agents interfere with the ability of the virus to bind to cells
• Some agents stimulate the body’s immune system

Common Respiratory Viruses

• Influenza A
• Influenza B
• Respiratory syncytial virus

Signs & Symptoms of Respiratory Viruses

• Cough
• Fever
• Inflammation of the nasal mucosa
• Inflammation of the mucosa of the respiratory tract

Signs and Symptoms of Herpes Virus

• Painful vesicles that often occur in clusters on skin, cornea, or mucous membranes
• Usual course of primary disease is 2 weeks
• Duration of recurrences varies

Signs and Symptoms of CMV

• May be asymptomatic
• Fatigue
• Nausea
• Jaundice
• If contracted during pregnancy, can result in stillbirth, brain damage, or birth defects

Signs and Symptoms of HIV/AIDS

• Attach helper T cells
• Acute infection: fever, rash, and myalgia
• Asymptomatic infection: follows acute infection; duration varies
• Persistent generalized lymphadenopathy: adenopathy persists more than 3 months
• Constitutional symptoms: fever lasting more than a month, involuntary weight loss, chronic fatigue
• Neurologic disease: dementia
• Secondary infections: pneumocystis carinii and disseminated herpes simplex

Influenza A & Respiratory Viruses

• Action: prevent shedding of the viral protein coat
• Pharmacokinetics: administered orally and excreted unchanged in the urine
• Contraindications: allergy, pregnancy, and lactation
• Adverse reactions: dizziness, insomnia, nausea, orthostatic hypotension
• Drug-to-drug interactions: anticholinergic agents

Herpes & Cytomegalovirus

• Action: inhibit viral DNA replication by competing with viral substrates to form shorter, noneffective DNA chains
• Pharmacokinetics: administered orally, IV, or topically; excreted unchanged in the urine
• Contraindications: pregnancy and lactation
• Adverse reactions: nausea, vomiting, headache, rash, and hair loss
• Drug-to drug-interactions: nephrotoxic drugs and zidovudine

Drugs Used to Treat HIV/AIDS

• Reverse transcriptase inhibitors
• Protease inhibitors
• Nucleosides
• Fusion inhibitors

Reverse Transcriptase Inhibitors

• Action: bind directly to HIV reverse transcriptase, blocking both RNA- and DNA-dependent DNA polymerase activities
• Pharmacokinetics: given orally, metabolized in the liver, and excreted in the urine
• Contraindications: pregnancy and lactation
• Adverse reactions: headache, nausea, vomiting, rash, chills, fever, and diarrhea

Protease Inhibitors

• Action: block protease activity within the HIV virus
• Pharmacokinetics: agents are teratogenic except for saquinavir
• Contraindications: pregnancy and lactation

Nucleosides

• Action: interfere with HIV replication by inhibiting cell protein synthesis
• Pharmacokinetics: given orally or IV, metabolized in the liver, and excreted in the urine
• Adverse reactions: HA, insomnia, dizziness, nausea, diarrhea, fever, and rash

Fusion Inhibitors

• Action: prevent the fusion of the virus with the human cellular membrane
• Pharmacokinetics: given sub-q, metabolized in the liver, recycled in the tissues, and not excreted
• Contraindication: no true contraindication
• Adverse reactions: HA, dizziness, myalgia, nausea, vomiting, and diarrhea
• Drug-to-drug interactions: pimozide, rifampin, triazolam, midazolam, and oral contraceptives

Locally Active Antiviral Agents

• Action: act on viruses by interfering with normal viral replication and metabolic processes
• Pharmacokinetics: not absorbed systemically
• Contraindication: allergy to the drug
• Adverse reactions: local burning, stinging, and discomfort

Prototype of Respiratory Antiviral Agents

Prototype of Herpes and Cytomegalovirus Agents

Prototype of HIV/AIDS Antiviral Agents

 

Nursing Considerations for Respiratory Antiviral Therapy

• Assessment (history and physical exam)
• Nursing diagnosis
• Implementation
• Evaluation

Nursing Considerations for Herpes Virus and Cytomegalovirus

• Assessment (history and physical exam)
• Nursing diagnosis
• Implementation
• Evaluation

Nursing Considerations for HIV/AIDS Antiviral Therapy

• Assessment (history and physical exam)
• Nursing diagnosis
• Implementation
• Evaluation

Nursing Considerations for Locally Active Antiviral Agents

• Assessment (history and physical exam)
• Nursing diagnosis
• Implementation
• Evaluation